The nanofluid as a pivotal role in heat transfer system has attracted more and more attention. Herein, the stearic acid-modified CuS (SA-CuS) nanoparticles with a uniform diameter of 60 nm were synthesized successfully by a facile two-phase approach. Accordingly, the CuS-oil nanofluids, with SA-CuS concentrations ranging from 0.01 to 0.04 vol%, were prepared by a one-step method in the heat transfer oil. These CuS-oil nanofluids exhibit good stability and considerable enhanced thermal conductivity. The improvement is even up to 20.5% with a volume fraction of 0.04 vol% at 30 °C. Furthermore, the effect of volume fraction and temperature on the viscosity of the nanofluids was also systematically investigated.

The high efficiency of cathode catalyst used in the oxygen reduction reaction is a vital factor guaranteeing for the microbial fuel cells (MFCs). In this work, two novel nickel cobaltite@nanocarbon hybrids were rationally designed and successfully prepared as efficient cathode catalysts in air–cathode MFCs. Impressively, the achieved maximum power density of the MFCs equipped with NiCo2O4@MWCNTs cathode was about 356 mW m−2, which is significantly higher than that of the MFCs with other cathodic catalysts. This work may provide not only the fundamental studies on nanocarbon-supported mixed-valent transition-metal oxides but also a new kind of promising alternative electrode in the technology of power generation from MFCs.

Microbial fuel cells (MFCs), as an ideal device, are highly attractive for renewable and sustainable energy storage. On the other hand, the development of low-cost and efficient catalysts based on earth-abundant elements for the sluggish oxygen reduction reaction (ORR) has remained elusive. Herein, a robust non-precious metal-based electrocatalyst is demonstrated, consisting of nitrogen-doped carbon hollow spheres elaborately decorated with Co3O4 nanoparticles (HCN-Co3O4). The unique structure of HCN-Co3O4 fully enables the utilization of synergistic effect of the high activity of Co3O4 and the excellent conductivity of HCN, endowing the hybrid with an excellent ORR catalytic activity in MFCs. Benefiting from intriguing structural features, HCN-Co3O4 exhibits a significantly enhanced electrocatalytical performance towards the ORR both in alkaline and neutral conditions, superior cycling stability, and outstanding durability compared to pure Co3O4 and hollow Co3O4 (H-Co3O4) spheres. Moreover, the high power density of the self-assembled MFCs equipped with the HCN-Co3O4 cathode also indicates the feasibility of the catalyst for practical applications.

Microbial fuel cells (MFCs), as an ideal device, are highly attractive for renewable and sustainable energy storage. On the other hand, the development of low-cost and efficient catalysts based on earth-abundant elements for the sluggish oxygen reduction reaction (ORR) has remained elusive. Herein, a robust non-precious metal-based electrocatalyst is demonstrated, consisting of nitrogen-doped carbon hollow spheres elaborately decorated with Co3O4 nanoparticles (HCN-Co3O4). The unique structure of HCN-Co3O4 fully enables the utilization of synergistic effect of the high activity of Co3O4 and the excellent conductivity of HCN, endowing the hybrid with an excellent ORR catalytic activity in MFCs. Benefiting from intriguing structural features, HCN-Co3O4 exhibits a significantly enhanced electrocatalytical performance towards the ORR both in alkaline and neutral conditions, superior cycling stability, and outstanding durability compared to pure Co3O4 and hollow Co3O4 (H-Co3O4) spheres. Moreover, the high power density of the self-assembled MFCs equipped with the HCN-Co3O4 cathode also indicates the feasibility of the catalyst for practical applications.

The exploration and design of inexpensive noble-free metal catalysts with high activity and stability as alternatives for carbon supported platinum catalysts (Pt/C) in the microbial fuel cells (MFCs) still remain a great challenge. In this work, nanostructured hexagonal klockmannite copper selenide (CuSe) grown on the hybrid of reduction oxidized graphene (rGO) and carbon nanotubes (CNTs) has been synthesized via a facile and cost effective method. Compared with the pure CuSe, rGO-CNTs and correlative others, the as-prepared CuSe@rGO-CNTs exhibited a superior ORR catalytic performance, for instance, more positive onset potential, higher current density, smaller Tafel slope and excellent stability. Furthermore, MFCs equipped with CuSe@rGO-CNTs cathodes also achieved a larger energy output comparable to those of reference devices employing Pt/C as the catalyst.

•Er2O3@ZnO core-shell nanorods were successfully fabricated by an electrochemical process.•The as-prepared composites exhibited improved photocurrent under the light irradiation.•The results indicate that the composites hold great promise for PEC water splitting.In this study, we demonstrated large-scale Er2O3@ZnO core-shell nanorods with great photoelectrochemical water splitting ability, which were successfully fabricated by a simple and facile electrodeposition. These Er2O3@ZnO core-shell nanorods exhibited improved photocurrent under the light irradiation, which can be attributed to the enhanced donor density by the covered Er2O3.In this paper, we reported a facile method to prepare Er2O3@ZnO core-shell composites and examined their applications as photo-anodes in photoelectrochemical water splitting. The as-fabricated composites exhibited improved photocurrent under the light irradiation, which can be attributed to the enhanced donor density by the covered Er2O3.

The exploration and design of inexpensive noble-free metal catalysts with high activity and stability as alternatives for carbon supported platinum catalysts (Pt/C) in the microbial fuel cells (MFCs) still remain a great challenge. In this work, nanostructured hexagonal klockmannite copper selenide (CuSe) grown on the hybrid of reduction oxidized graphene (rGO) and carbon nanotubes (CNTs) has been synthesized via a facile and cost effective method. Compared with the pure CuSe, rGO-CNTs and correlative others, the as-prepared CuSe@rGO-CNTs exhibited a superior ORR catalytic performance, for instance, more positive onset potential, higher current density, smaller Tafel slope and excellent stability. Furthermore, MFCs equipped with CuSe@rGO-CNTs cathodes also achieved a larger energy output comparable to those of reference devices employing Pt/C as the catalyst.

Microbial fuel cells (MFCs), as an ideal device, are highly attractive for renewable and sustainable energy storage. On the other hand, the development of low-cost and efficient catalysts based on earth-abundant elements for the sluggish oxygen reduction reaction (ORR) has remained elusive. Herein, a robust non-precious metal-based electrocatalyst is demonstrated, consisting of nitrogen-doped carbon hollow spheres elaborately decorated with Co3O4 nanoparticles (HCN-Co3O4). The unique structure of HCN-Co3O4 fully enables the utilization of synergistic effect of the high activity of Co3O4 and the excellent conductivity of HCN, endowing the hybrid with an excellent ORR catalytic activity in MFCs. Benefiting from intriguing structural features, HCN-Co3O4 exhibits a significantly enhanced electrocatalytical performance towards the ORR both in alkaline and neutral conditions, superior cycling stability, and outstanding durability compared to pure Co3O4 and hollow Co3O4 (H-Co3O4) spheres. Moreover, the high power density of the self-assembled MFCs equipped with the HCN-Co3O4 cathode also indicates the feasibility of the catalyst for practical applications.

Microbial fuel cells (MFCs), as an ideal device, are highly attractive for renewable and sustainable energy storage. On the other hand, the development of low-cost and efficient catalysts based on earth-abundant elements for the sluggish oxygen reduction reaction (ORR) has remained elusive. Herein, a robust non-precious metal-based electrocatalyst is demonstrated, consisting of nitrogen-doped carbon hollow spheres elaborately decorated with Co3O4 nanoparticles (HCN-Co3O4). The unique structure of HCN-Co3O4 fully enables the utilization of synergistic effect of the high activity of Co3O4 and the excellent conductivity of HCN, endowing the hybrid with an excellent ORR catalytic activity in MFCs. Benefiting from intriguing structural features, HCN-Co3O4 exhibits a significantly enhanced electrocatalytical performance towards the ORR both in alkaline and neutral conditions, superior cycling stability, and outstanding durability compared to pure Co3O4 and hollow Co3O4 (H-Co3O4) spheres. Moreover, the high power density of the self-assembled MFCs equipped with the HCN-Co3O4 cathode also indicates the feasibility of the catalyst for practical applications.