•A preparation strategy for low Pd-loading PdAg catalyst was developed.•Ag additive was found to benefit both Pd utilization and catalyst stability.•The catalyst showed a TOF of 171 mol Pd−1 h−1 towards formic acid decomposition.As an interesting hydrogen carrier, formic acid is bio-renewable, non-toxic and available in the liquid state at room temperature. The development of active and low-cost catalyst is of significance for hydrogen generation from formic acid. In this study, both a relatively cheap metal (Ag) and a functional support (nitrogen modified reduced graphene oxide, N-rGO) were applied to prepare Pd catalyst. It was found that the Ag atoms facilitated the formation of Pd-rich surface in the preparation strategy, in which the reductive N-rGO and a two-step feeding process of metal precursors played important roles. In addition, Ag additive was found to benefit catalyst stability. Most interestingly, the obtained low Pd-loading Pd1Ag6/N-rGO catalyst showed a specific Pd loading turnover frequency of 171 mol Pd−1 h−1 and a specific metal cost turnover frequency of 64.2 $−1 h−1, which were predominant among currently available Pd-based catalysts towards formic acid decomposition without any additive under room temperature.

A method combining protein extraction with hydride generation-atomic fluorescence spectrometer was developed to analyze protein-based arsenic (PBA) present in popular shrimp of China. The traditional method of alkali extraction-isoelectric precipitation was used for protein extraction, and microwave was applied for sample digestion. It was found that PBA concentrations in the extracted proteins were 0.626, 4.01, and 5.91 μg/g for meat, shell, and visceral samples, respectively. PBA recoveries of between 89.72 and 102.3 % were obtained by using the extracted proteins from meat as “standard proteins.” The results of sample and time variability tests showed that PBA concentrations in shrimp samples were very stable. The obtained total arsenic concentration in meat was only 0.123 μg/g and indicated humans’ low daily intake of arsenic from this kind of Chinese shrimp.