6 research outputs found
Refining Energy Levels in ReS 2 Nanosheets by LowâValent TransitionâMetal Doping for DualâBoosted Electrochemical Ammonia/Hydrogen Production
Electrocatalytic nitrogen reduction reaction (NRR) and hydrogen evolution reaction (HER) are intriguing approaches to nitrogen fixation and hydrogen production under ambient conditions, given the need to discover efficient and stable catalysts to light up the âgreen chemistryâ future. However, bottlenecks are often found during N2/H2O activation, the very first step of NRR/HER, due to energetic electron injection from the surface of electrocatalysts. It is reported that the bottlenecks for both NRR and HER can be tackled by engineering the energy level via lowâvalent transitionâmetal doping, simultaneously, where rhenium disulfide (ReS2) is employed as a model platform to prove the concept. The doped lowâvalent transitionâmetal domains (e.g., Fe, Co, Ni, Cu, Zn) in ReS2 provide more active sites for N2/H2O chemisorption and electron transfer, not only weakening the NN/OH bonds for easier dissociation through proton coupling, but also elevating dâband center toward the Fermi level with more electron energy for N2/H2O reduction. As a result, it is found that ironâdoped ReS2 nanosheets wrapped nitrogenâdoped carbon nanofiber (FeâReS2@NâCNF) catalyst exhibits superior electrochemical activity with eightfold higher ammonia production yield of 80.4 ”g hâ1 mgâ1cat., and lower onset overpotential of 146 mV and Tafel slope of 63 mV decâ1, when comparing with the pristine ReS2