Co-reporter:Cui Lu, Jianying Wang, Steffen Czioska, Huan Dong, and Zuofeng Chen
The Journal of Physical Chemistry C November 22, 2017 Volume 121(Issue 46) pp:25875-25875
Publication Date(Web):October 31, 2017
DOI:10.1021/acs.jpcc.7b08365
We report here the fabrication of CuO nanowires and their use as efficient electrocatalyst for the oxygen evolution reaction (OER) or as precursor for preparation of Cu3P nanowires for the hydrogen evolution reaction (HER). The surface-bound Cu(OH)2 nanowires are in situ grown on a three-dimensional copper foam (CF) by anodic treatment, which are then converted to CuO nanowires by calcination in air. The direct growth of nanowires from the underlying conductive substrate can eliminate the use of any conductive agents and binders, which ensures good electrical contact between the electrocatalyst and the conductive substrate. The hierarchically nanostructured Cu-based electrode exhibits excellent catalytic performance toward OER in 1 M KOH solution. Phosphorization of the CuO/CF electrode generates the Cu3P/CF electrode, which can act as an excellent electrocatalyst for HER in 1 M KOH. An alkaline electrolyzer is constructed using CuO and Cu3P nanowires coated copper foams as anode and cathode, which can realize overall water splitting with a current density of 102 mA/cm2 at an applied cell voltage of 2.2 V.
Co-reporter:Lvlv Ji, Jianying Wang, Shangshang Zuo, and Zuofeng Chen
The Journal of Physical Chemistry C April 27, 2017 Volume 121(Issue 16) pp:8923-8923
Publication Date(Web):April 10, 2017
DOI:10.1021/acs.jpcc.7b01447
We describe here that the electrode materials toward the hydrogen evolution reaction (HER) can be cathodically activated by anodic dissolution of Pt counter electrode, dependent on the nature of substrate materials and solution pH. It leads to a direct approach for in situ fabrication of a highly dispersed and active HER electrocatalyst with minimal Pt loading that requires only a piece of Pt (instead of Pt salt, such as K2PtCl6) as Pt source combined with judicious choices of substrate materials and electrolyte solution. For a typical sample obtained by pyrolyzing poly(2,6-diaminopyridine) (PDAP) under ammonia atmosphere followed by successive cyclic voltammetry scans in 0.5 M H2SO4, a current density of 60 mA cm–2 was obtained at an overpotential of only 50 mV. Although the Pt loading is only 1.5 wt % in the sample, this performance is even better than that of the commercial 20 wt % Pt/C. The experimental results indicate that the deposited Pt nanoparticles are highly dispersed on the electrode substrate with a size of 2–4 nm. Further experimental results suggest that the combination of three factors, including the slow release of Pt into solution, high specific surface area of the substrate materials, and homogeneously doped N atoms acting as Pt anchor sites, is the key for formation of the highly active Pt nanoparticles. This study thus also raises an alarm regarding the use of Pt counter electrode in HER catalysis, especially by N-doped carbon in an acidic solution.
Co-reporter:Lvlv Ji;Jianying Wang;Lixia Guo
Journal of Materials Chemistry A 2017 vol. 5(Issue 10) pp:5178-5186
Publication Date(Web):2017/03/07
DOI:10.1039/C6TA10145C
We report here a unique in situ O2-emission assisted synthesis method to prepare molybdenum carbide (MoxC) nanomaterials with dense active sites and high effective surface area. The key to this protocol is the delicate design and synthesis of polymeric hybrid precursors by taking advantage of the synergy among the reactants. Oxidative polymerization of aniline (ANI) to form polyaniline (PANI), which acted as the nitrogen-rich carbon source, was initiated by adding aqueous H2O2 instead of the conventionally used ammonium persulfate (APS), and phosphomolybdate anions (PMo12) were doped into the positively charged PANI matrix via coulombic interactions. During the polymerization, vigorous O2 bubbles were in situ produced by H2O2 decomposition catalyzed by PMo12, which mechanically broke down the precursor into nanosized polymeric hybrids with a porous and loose morphology. The MoxC electrocatalyst was optimized by varying the feeding content of PMo12 and carbonization temperature, exhibiting remarkable catalytic activity and stability toward the hydrogen evolution reaction (HER) in both acidic and alkaline solutions. It requires an overpotential of only 144 mV and 141 mV to reach a current density of 10 mA cm−2 in 0.5 M H2SO4 and in 1 M NaOH, respectively, making it among the best of the reported MoxC-based electrocatalysts.
Co-reporter:Jianying Wang;Lvlv Ji;Shangshang Zuo
Advanced Energy Materials 2017 Volume 7(Issue 14) pp:
Publication Date(Web):2017/07/01
DOI:10.1002/aenm.201700107
A NiFe-based integrated electrode is fabricated by the spontaneous galvanic replacement reaction on an iron foam. Driven by the different electrochemical potentials between Ni and Fe, the dissolution of surface Fe occurs with electroless plating of Ni on iron foam with no need to access instrumentation and input energy. A facile cyclic voltammetry treatment is subsequently applied to convert the metallic NiFe to NiFeOx. A series of analytical methods indicates formation of a NiFeOx film of nanosheets on the iron foam surface. This hierarchically structured three dimensional electrode displays high activity and durability against water oxidation. In 1 m KOH, a current density of 1000 mA cm−2 is achieved at an overpotential of only 300 mV. This method is readily extended to fabricate CoFe or NiCoFe-based integrated electrodes for water oxidation. Phosphorization of the bimetallic oxide (NiFeOx) generates the bimetallic phosphide (NiFe-P), which can act as an excellent electrocatalyst for hydrogen production in 1 m KOH. An alkaline electrolyzer is constructed using NiFeOx and NiFe-P coated iron foams as anode and cathode, which can realize overall water splitting with a current density of 100 mA cm−2 at an overpotential of 630 mV.
Co-reporter:Shangshang Zuo, Hongxia Bai, Qi Han, Hong-Gang Liao, Hongbo Gu, Zuofeng Chen
Materials & Design 2017 Volume 114(Volume 114) pp:
Publication Date(Web):15 January 2017
DOI:10.1016/j.matdes.2016.10.033
•The magnetic nanocomposites were prepared by calcining Fe(NO3)3 and carbon precursor mixture in Ar and at low temperature.•The magnetic property was tuned by varying calcination temperature, gas flow rate, retention time, and heating rate.•The saturation magnetization relies on the spatial and temporal contact of Fe intermediates with NO2 and O2 byproducts.We report here that carbon-coated magnetic nanocomposites can be prepared by calcination of the mixture of ferric nitrate (Fe(NO3)3) and hydroxyethyl cellulose under argon atmosphere (without hydrogen) and at low temperature (400 °C). The magnetic property of the as-prepared samples can be tuned by simply varying the calcination temperature, the flow rate of argon, the retention time, and the heating rate. The characterization of these samples by XRD, FTIR, TEM and XPS reveals that their magnetic property is closely related with the contents of Fe3O4 and Fe2O3 in these samples. The proposed mechanism indicates that the reduction of the spatial and temporal contact of the decomposed Fe intermediates with the NO2 and O2 byproducts would be favorable for the formation of Fe3O4, leading to the higher saturation magnetization of the samples.We report that carbon-coated magnetic nanocomposites can be prepared by calcination of the mixture of ferric nitrate (Fe(NO3)3) and hydroxyethyl cellulose under benign calcination conditions (argon atmosphere, 400 °C). The magnetic property of the as-prepared samples can be tuned by simply varying the calcination temperature, the flow rate of argon, the retention time, and the heating rate, which would have important implication for the use of Fe(NO3)3 as iron source for future preparation of carbon-coated magnetic nanocomposites with high saturation magnetization.Download high-res image (205KB)Download full-size image
Co-reporter:Weiqiang Tang, Shangshang Zuo, Jianying Wang, Yongli Mi, Zuofeng Chen
Electrochimica Acta 2017 Volume 247(Volume 247) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.electacta.2017.07.075
Herein, nanostructured FeOOH supported on the 3D nickel foam (FeOOH-NF) was prepared by a facile one-pot hydrothermal deposition. A series of analytical techniques indicate formation of a layered uniform nanosheets from the underlying nickel foam which incorporate in situ generated FeOOH. Thanks to the synergistic interaction between Fe and Ni and the good electrical connection between the active catalyst and conductive substrate by the direct growth, the hierarchically structured electrode exhibits high electrocatalytic performance for the oxygen evolution reaction (OER) in alkaline solution with low overpotential, small Tafel slope and excellent long-term durability. In 1 M KOH, a current density of 20 mA/cm2 is achieved at an overpotential of only 210 mV with a Tafel slope of 29 mV/decade, which is competitive or superior to various electrocatalysts on the 3D nickel foam under similar conditions. Considering the simple and facile electrode preparation, the low cost and environmental friendliness of the electrode materials, and the excellent catalytic performance, the FeOOH-NF electrode would be a promising anode candidate for the OER in large scale water electrolysis.Download high-res image (187KB)Download full-size image
Co-reporter:Lvlv Ji, Lei Zhu, Jianying Wang, Zuofeng Chen
Electrochimica Acta 2017 Volume 252(Volume 252) pp:
Publication Date(Web):20 October 2017
DOI:10.1016/j.electacta.2017.09.008
A self-supported copper sulfide (CuS) nanowire array (NWA) of hierarchical and porous structure has been developed on Cu foil via two consecutive liquid-solid reactions at room temperature. The composition, structure and morphology of the as-prepared CuS NWA samples have been systematically investigated by a series of techniques. When applied as cathode for the hydrogen evolution reaction (HER) in neutral solution, the optimized CuS NWA electrode exhibits excellent HER performance with high long-term stability. To achieve current densities of 10 and 100 mA cm−2, it requires overpotentials of only ∼97 and ∼226 mV, respectively. The excellent catalytic performance of CuS NWA toward HER is attributable to the binder-free electrode construction strategy, the unique porous nanowire array structure, and the small solubility product (Ksp) value of CuS that guarantees the high catalyst stability.Download high-res image (201KB)Download full-size image
Co-reporter:Yangyang Liu;Xue Teng;Yongli Mi
Journal of Materials Chemistry A 2017 vol. 5(Issue 46) pp:24407-24415
Publication Date(Web):2017/11/28
DOI:10.1039/C7TA07795E
A facile and novel method of in situ growing a nickel–cobalt layered double hydroxide (Ni–Co LDH) nanosheet film on a three-dimensional Cu nanowire (NW) network on Cu foam is developed by three sequential electrochemical steps, which is free of any surfactant, stabilizer or organic binder. The hierarchically structured hybrid electrode is highly porous and endowed with greatly improved specific surface area, conductibility, and mechanical strength because of its unique structure with Cu NW networks crossed through Ni–Co LDH nanosheets. As pseudocapacitors, the as-prepared Ni–Co LDH hybrid electrode exhibits a significantly enhanced specific capacitance of 2170 F g−1 and an areal specific capacitance of 9.98 F cm−2 at 1 A g−1, which is comparable with or superior to most previously reported electrodes based on nickel–cobalt hydroxides. Moreover, the as-obtained electrode also exhibits an excellent rate capability with a specific capacitance of 1875 F g−1 even at a very high current density of 10 A g−1, which is about 86.4% of that at 1 A g−1. Besides, an excellent cycling performance is also obtained with a capacitance retention of 80.46% after 2000 cycles at a high current density of 6 A g−1, suggesting its promising application as an efficient electrode for electrochemical capacitors.
Co-reporter:Jianying Wang, LvLv Ji, and Zuofeng Chen
ACS Catalysis 2016 Volume 6(Issue 10) pp:6987
Publication Date(Web):September 9, 2016
DOI:10.1021/acscatal.6b01837
If an oxygen evolution reaction (OER) catalyst is expected to be more durable, especially under conditions of thin-layer catalysts or strong gas evolution, it will ideally function in a self-repair mode. In earlier studies, the electrochemical fabrications of Ni–Fe oxide catalysts were exclusively carried out by cathodic reduction of Ni(II) and Fe(III,II) in an individual solution that is different from the alkaline media commonly used for the OER. The procedure does not suggest that the dissolution/corrosion of the film catalysts could be countered by continual catalyst formation during the OER. Herein, we report a highly active NiFeOx catalyst by in situ rapid (3–15 min) anodic deposition of Ni(II) and Fe(III,II) in concentrated carbonate solution. At a transparent indium tin oxide (ITO) electrode, the conformal deposition of NiFeOx (7–11-atom layer) results in a very low optical loss (5–8%) with activity comparable to that of other planar NiFeOx films. Extension to a 3D nickel foam produces a hierarchical coating of grasslike structure. With few added Ni(II) and Fe(III) atoms to counter the film dissolution/corrosion, the catalyst can deliver a stable current density of 100 mA/cm2 at an overpotential of only 260 mV in alkaline media. This example of a NiFeOx catalyst forms during in situ OER and operates by a self-repair mode, highlighting a truly important feature for the practical application of this state of the art OER electrocatalyst.Keywords: electrocatalysis; in situ electrodeposition; NiFe oxide; transparent electrodes; water oxidation
Co-reporter:Cui Lu, Jialei Du, Xiao-Jun Su, Ming-Tian Zhang, Xiaoxiang Xu, Thomas J. Meyer, and Zuofeng Chen
ACS Catalysis 2016 Volume 6(Issue 1) pp:77
Publication Date(Web):November 12, 2015
DOI:10.1021/acscatal.5b02173
Simply mixing a Cu(II) salt and 1,2-ethylenediamine (en) affords precursors for both heterogeneous or homogeneous water oxidation catalysis, depending on pH. In phosphate buffer at pH 12, the Cu(II) en complex formed in solution is decomposed to give a phosphate-incorporated CuO/Cu(OH)2 film on oxide electrodes that catalyzes water oxidation. A current density of 1 mA/cm2 was obtained at an overpotential of 540 mV, a significant enhancement compared to other Cu-based surface catalysts. The results of electrolysis studies suggest that the solution en complex decomposes by en oxidation to glyoxal, following Cu(II) oxidation to Cu(III). At pH 8, the catalysis shifts from heterogeneous to homogeneous with a single-site mechanism for Cu(II)/en complexes in solution. A further decrease in pH to 7 leads to electrode passivation via the formation of a Cu(II) phosphate film during electrolyses. As the pH is decreased, en, with pKb ≈ 6.7, becomes less coordinating and the precipitation of the Cu(II) film inhibits water oxidation. The Cu(II)-based reactivity toward water oxidation is shared by Cu(II) complexation to the analogous 1,3-propylenediamine (pn) ligand over a wide pH range.Keywords: copper; heterogeneous catalysis; homogeneous catalysis; ligand dissociation; water oxidation
Co-reporter:Jialei Du, Jianying Wang, Lvlv Ji, Xiaoxiang Xu, and Zuofeng Chen
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 44) pp:30205
Publication Date(Web):October 17, 2016
DOI:10.1021/acsami.6b09975
Although significant progress has been made recently, copper-based materials have long been considered to be ineffective catalysts toward the hydrogen evolution reaction (HER), in most cases, requiring high overpotentials more than 300 mV. We report here that a Cu(0)-based nanoparticle film electrodeposited in situ from a Cu(II) oxime complex can act as a highly active and robust HER electrocatalyst in neutral phosphate buffer solution. The as-prepared nanoparticle film is of poor crystallization, which incorporates significant amounts of oxime ligand residues and buffer anions PO43–. The proposed mechanism suggests that the Cu(0)-based nanoparticle film is activated with incorporated or adsorbed PO43– anions and the PO43– anions-anchored sites might serve as the actual catalytic active sites with efficient proton transport mediators. Catalysis occurs with a low onset overpotential (η) of 65 mV, and a current density of 1 mA/cm2 can be achieved with η = 120 mV. The nanoparticle film shows an excellent catalytic durability with slightly rising current density during electrolysis, presumably due to further incorporation or adsorption of PO43– anions in the process. This electrocatalyst not only forms in situ from earth-abundant materials but also operates in neutral water with low overpotential and high stability.Keywords: Cu-based nanoparticle film; electrodeposition; heterogeneous electrocatalysis; hydrogen evolution reaction; neutral pH
Co-reporter:Lei Zhu, Jialei Du, Shangshang Zuo, and Zuofeng Chen
Inorganic Chemistry 2016 Volume 55(Issue 14) pp:7135-7140
Publication Date(Web):June 28, 2016
DOI:10.1021/acs.inorgchem.6b01122
We report here a new catalytic water oxidation system based on Cu(II) ions and a remarkable countercation effect on the catalysis. In a concentrated fluoride solution at neutral to weakly basic pHs, simple Cu(II) salts are highly active and robust in catalyzing water oxidation homogeneously. F– in solution acts as a proton acceptor and an oxidatively robust ligand. F– coordination prevents precipitation of Cu(II) as CuF2/Cu(OH)2 and lowers potentials for accessing high-oxidation-state Cu by delocalizing the oxidative charge over F– ligands. Significantly, the catalytic current is greatly enhanced in a solution of CsF compared to those of KF and NaF. Although countercations are not directly involved in the catalytic redox cycle, UV–vis and 19F nuclear magnetic resonance measurements reveal that coordination of F– to Cu(II) is dependent on countercations by Coulombic interaction. A less intense interaction between F– and well-solvated Cs+ as compared with Na+ and K+ leads to a more intense coordination of F– to Cu(II), which accounts for the improved catalytic performance.
Co-reporter:Steffen Czioska and Zuofeng Chen
RSC Advances 2016 vol. 6(Issue 8) pp:6583-6588
Publication Date(Web):11 Jan 2016
DOI:10.1039/C5RA24111A
Sensitivity is a key parameter for electrogenerated chemiluminescence (ECL) analysis. We describe here a simple way to enhance the ECL of Ru(bpy)32+ (bpy = 2,2′-bipyridine) by adding concentrated perchlorate salts. Observations are made for a variety of aliphatic amines as coreactants in a wide pH range from pH 5 to 12 with ECL enhanced by 1.5–6.6 times for different ECL routes. By contrast, the addition of other salts such as nitrate, sulfate and chloride decreases ECL to some extent. Experimental studies suggest that perchlorate anions could stabilize the coreactant cation radicals by formation of ion pairs, which allows ECL to occur in a thicker reaction layer by a longer travel distance of these intermediates. However, other anions may get involved in detrimental redox processes. For example, nitrate and sulfate may directly react with the highly reducing coreactant free radicals or Ru(bpy)3+ intermediates, and chloride may be concomitantly oxidized at the electrode surface during ECL emission generating highly reactive HClO/ClO− intermediates. This study is important for both mechanistic fundamentals and the realistic applications of ECL.
Co-reporter:Cui Lu;Jianying Wang ; Zuofeng Chen
ChemCatChem 2016 Volume 8( Issue 12) pp:2165-2170
Publication Date(Web):
DOI:10.1002/cctc.201600261
Abstract
Although notable progress has been made in developing first-row transition-metals-based water oxidation catalysts, continuous efforts are required to identify more inexpensive, efficient, and robust catalysts. Here, we demonstrate the utility of a series of readily available complexes formed by earth-abundant copper and amino acids as catalyst precursors. In phosphate solution at pH 12, electrolysis with 1 mm CuII and 4 mm Gly results in in situ formation of an amorphous surface precipitate of a CuO/Cu(OH)2 mixture, which incorporates a substantial amount of phosphate anions. This surface-bound solid can catalyze water oxidation with an impressive onset overpotential of 380 mV, an overpotential of 450 mV for a current density of 1 mA cm−2, and a low Tafel slope of 64 mV dec−1, which make it among the most active Cu-based heterogeneous electrocatalysts. The copper-based reactivity toward water oxidation is shared by CuII complexation to other amino acids as catalyst precursors.
Co-reporter:Jialei Du; Zuofeng Chen; Chuncheng Chen;Thomas J. Meyer
Journal of the American Chemical Society 2015 Volume 137(Issue 9) pp:3193-3196
Publication Date(Web):February 20, 2015
DOI:10.1021/jacs.5b00037
Chloride oxidation to chlorine is a potential alternative to water oxidation to oxygen as a solar fuels half-reaction. Ag(I) is potentially an oxidative catalyst but is inhibited by the high potentials for accessing the Ag(II/I) and Ag(III/II) couples. We report here that the complex ions AgCl2– and AgCl32– form in concentrated Cl– solutions, avoiding AgCl precipitation and providing access to the higher oxidation states by delocalizing the oxidative charge over the Cl– ligands. Catalysis is homogeneous and occurs at high rates and low overpotentials (10 mV at the onset) with μM Ag(I). Catalysis is enhanced in D2O as solvent, with a significant H2O/D2O inverse kinetic isotope effect of 0.25. The results of computational studies suggest that Cl– oxidation occurs by 1e– oxidation of AgCl32– to AgCl3– at a decreased potential, followed by Cl– coordination, presumably to form AgCl42– as an intermediate. Adding a second Cl– results in “redox potential leveling”, with further oxidation to {AgCl2(Cl2)}− followed by Cl2 release.
Co-reporter:Jialei Du; Zuofeng Chen;Dr. Shengrong Ye; Benjamin J. Wiley; Thomas J. Meyer
Angewandte Chemie International Edition 2015 Volume 54( Issue 7) pp:2073-2078
Publication Date(Web):
DOI:10.1002/anie.201408854
Abstract
Copper metal is in theory a viable oxidative electrocatalyst based on surface oxidation to CuIII and/or CuIV, but its use in water oxidation has been impeded by anodic corrosion. The in situ formation of an efficient interfacial oxygen-evolving Cu catalyst from CuII in concentrated carbonate solutions is presented. The catalyst necessitates use of dissolved CuII and accesses the higher oxidation states prior to decompostion to form an active surface film, which is limited by solution conditions. This observation and restriction led to the exploration of ways to use surface-protected Cu metal as a robust electrocatalyst for water oxidation. Formation of a compact film of CuO on Cu surface prevents anodic corrosion and results in sustained catalytic water oxidation. The Cu/CuO surface stabilization was also applied to Cu nanowire films, which are transparent and flexible electrocatalysts for water oxidation and are an attractive alternative to ITO-supported catalysts for photoelectrochemical applications.
Co-reporter:Jialei Du; Zuofeng Chen;Dr. Shengrong Ye; Benjamin J. Wiley; Thomas J. Meyer
Angewandte Chemie 2015 Volume 127( Issue 7) pp:2101-2106
Publication Date(Web):
DOI:10.1002/ange.201408854
Abstract
Copper metal is in theory a viable oxidative electrocatalyst based on surface oxidation to CuIII and/or CuIV, but its use in water oxidation has been impeded by anodic corrosion. The in situ formation of an efficient interfacial oxygen-evolving Cu catalyst from CuII in concentrated carbonate solutions is presented. The catalyst necessitates use of dissolved CuII and accesses the higher oxidation states prior to decompostion to form an active surface film, which is limited by solution conditions. This observation and restriction led to the exploration of ways to use surface-protected Cu metal as a robust electrocatalyst for water oxidation. Formation of a compact film of CuO on Cu surface prevents anodic corrosion and results in sustained catalytic water oxidation. The Cu/CuO surface stabilization was also applied to Cu nanowire films, which are transparent and flexible electrocatalysts for water oxidation and are an attractive alternative to ITO-supported catalysts for photoelectrochemical applications.
Co-reporter:Yaokang Lv, Weishi Du, Yan Ren, Zhiwei Cai, Kuai Yu, Cheng Zhang, Zuofeng Chen and Dominic S. Wright
Inorganic Chemistry Frontiers 2016 - vol. 3(Issue 9) pp:NaN1123-1123
Publication Date(Web):2016/06/27
DOI:10.1039/C6QI00114A
The novel heterometallic polyoxotitanate cage [Ti8O7(OEt)21Er] can be used as a single-source precursor for the formation of nanostructured Er-containing titania materials (Er@TiO2). Based on the electrochromic properties and lithium ion storage capacity of Er@TiO2, an integrated bifunctional EC supercapacitor has been designed.
Co-reporter:Lvlv Ji, Jianying Wang, Lixia Guo and Zuofeng Chen
Journal of Materials Chemistry A 2017 - vol. 5(Issue 10) pp:NaN5186-5186
Publication Date(Web):2017/02/08
DOI:10.1039/C6TA10145C
We report here a unique in situ O2-emission assisted synthesis method to prepare molybdenum carbide (MoxC) nanomaterials with dense active sites and high effective surface area. The key to this protocol is the delicate design and synthesis of polymeric hybrid precursors by taking advantage of the synergy among the reactants. Oxidative polymerization of aniline (ANI) to form polyaniline (PANI), which acted as the nitrogen-rich carbon source, was initiated by adding aqueous H2O2 instead of the conventionally used ammonium persulfate (APS), and phosphomolybdate anions (PMo12) were doped into the positively charged PANI matrix via coulombic interactions. During the polymerization, vigorous O2 bubbles were in situ produced by H2O2 decomposition catalyzed by PMo12, which mechanically broke down the precursor into nanosized polymeric hybrids with a porous and loose morphology. The MoxC electrocatalyst was optimized by varying the feeding content of PMo12 and carbonization temperature, exhibiting remarkable catalytic activity and stability toward the hydrogen evolution reaction (HER) in both acidic and alkaline solutions. It requires an overpotential of only 144 mV and 141 mV to reach a current density of 10 mA cm−2 in 0.5 M H2SO4 and in 1 M NaOH, respectively, making it among the best of the reported MoxC-based electrocatalysts.
