have been developed as NRR electrocatalysts. However, it remains a great challenge to design and develop novel NRR electrocatalysts in considering the high bond energy of NN (940.95 kJ mol −1 ) and the competitive hydrogen evolution reaction (HER) at harshly negative potential.Recently, transition-metal dichalcogenides (TMDs) have been reported for their excellent electrocatalytic NRR performance. [13][14][15][16] Among them, transition metal sulfides (TMSs) emerged as efficient NRR electrocatalysts working under ambient conditions because that the presence of transition metal and sulfur (S) atoms in TMSs offers similar coordination environment to the active sites of nitrogenase. [17,18] For example, Sun et al. [19] reported MoS 2 as an effective NRR electrocatalyst, proving that the positively charged Mo-edge in MoS 2 can activate and polarize the N 2 molecules. Chu et al. [20] demonstrated that a doping strategy can effectively activate vanadium disulfide (VS 2 ) basal planes by generating unsaturated-V active sites, thus significantly promoting NRR performance. Nevertheless, we noted that most of the previous works on TMSs based NRR electrocatalysts are only limited to unraveling the metal atoms as active sites, illustrating the N 2 activation mechanism, or regulating the activity by doping strategies. Unfortunately, the critical role of S sites in the NRR has been largely ignored, and the strategy of enhancing the activity of TMSs by tailoring S sites is rarely reported. In general, TMSs based electrocatalysts confront the serious competition of HER during NRR, leading to poor FE and low NH 3 yield. Specifically, previous works have been verified that the S edge site and V edge site of VS 2 are easy to chemisorb H + and N 2 . [21,22] In addition, the HER activity of TMSs mainly derives from the S edges, while the bulk part is inert for HER. [23][24][25] Meanwhile, the adsorption of N 2 molecules at the transition metal atoms sites, which is a crucial step for subsequent activation process, also is unavoidably blocked due to the existence of S edges at the surface of TMSs. [26] In considering the above aspects, we speculate that shearing the S edges might offer good opportunity of promoting the electrocatalytic performance of TMSs electrocatalysts by inhibiting HER and boosting NRR activity. Therefore, it is meaningful to develop new TMSs electrocatalyst based on a deliberately designed shearing S edges strategy Electrochemical N 2 fixation requires effective electrocatalysts to expedite the nitrogen reduction reaction (NRR) kinetics and suppress the concomitant hydrogen evolution reaction (HER). Although transition metal sulfides have been deemed as efficient NRR electrocatalysts, it remains a great challenge to suppress the serious HER to achieve high Faradaic efficiency (FE). Herein, vanadium disulfide (VS 2 ) is deliberately designed by partially shearing its sulfur (S) edges through a simple calcination treatment at 350 °C. The as-prepared VS 2 -350 electrocatalyst exhibits a highest NH 3 yield of 20.29 ...

Electrochemical nitrogen reduction reaction (NRR) is an effective method for sustainable production of NH3. However, a robust NRR electrocatalyst is predominantly required in order to active the inert N2 molecule....

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Direct formate fuel cells (DFFCs) have drawn tremendous attention because they are environmentally benign and have good safety. However, the lack of advanced catalysts for formate electrooxidation hinders the development and applications of DFFCs. Herein, we report a strategy of regulating the metal−substrate work function difference to effectively promote the transfer of adsorbed hydrogen (H ad ), thus enhancing formate electrooxidation in alkaline solutions. By introducing rich oxygen vacancies, the obtained catalysts of Pd/WO 3−x -R show outstanding formate electrooxidation activity, exhibiting an extremely high peak current of 15.50 mA cm −2 with a lower peak potential of 0.63 V. In situ electrochemical Fourier transform infrared and in situ Raman measurements verify an enhanced in situ phase transition from WO 3−x to H x WO 3−x during the formate oxidation reaction process over the Pd/WO 3−x -R catalyst. The results of experimental and density functional theory (DFT) calculations confirm that the work function difference (ΔΦ) between the metal (Pd) and substrate (WO 3−x ) would be regulated by inducing oxygen vacancies in the substrate, resulting in improved hydrogen spillover at the interface of the catalyst, which is essentially responsible for the observed high performance of formate oxidation. Our findings provide a novel strategy of rationally designing efficient formate electrooxidation catalysts.