Preparation And Properties Of Polymetallic Alloy Nanocatalysts For Hydrogen Production Applications

Under the strategic requirement of sustainable development,it is urgent to find clean energy to replace traditional energy which is non-renewable with serious pollution.Hydrogen has attracted much attention due to its advantages of wide sources,high energy density and no pollution.Water splitting and decomposition of formic acid are common hydrogen production technologies,and the development of cheap,efficient and long-term stable catalysts is the key to the development of hydrogen production technologies.Metal alloy nanomaterials have attracted extensive research due to their small size,large specific surface area and abundant surface active sites.In addition,the synergistic effect between metals and the role of carriers are conducive to enhancing the catalytic effect.Based on this,we have explored and synthesized two kinds of nanomaterials to catalyze the hydrogen production reaction,providing ideas for the synthesis of efficient catalysts.1.Mn-NiCo(OH)2 nanoarrays vertically arranged on 3D nickel foam are synthesized by hydrothermal method for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)under alkaline conditions.The nanoarray is formed by combining preferentially generated nanosheets with nanoneedle structures grown thereon.Electrochemical tests show that Mn-NiCo(OH)2 only needs 390 mV overpotential to drive the current density of 50 MA cm-2 for OER.For HER,a current density of 10 mA cm-2 can be driven when the overpotential is 157 mV.The characterization results and electrochemical tests confirm that the doping of Mn element changed the original electronic structure,thus improving its electrochemical performance.2.A bifunctional electrocatalyst with high activity and strong stability under alkaline conditions is synthesized.The target product-Mn-NiCoS2 is synthesized by vulcanization with Mn-NiCo(OH)2 as precursor.Electrochemical test results show that doping Mn element can improve the OER and HER performance of NiCo sulfide,and the optimal doping amount is 7.5%.And compared with hydroxide,the OER and HER performance of sulfide are stronger.The characterization results show that adding Mn element regulates the electron distribution of the catalyst,thus improving the electrocatalytic performance.In addition,when Mn-NiCoS2 is applied to be both cathode and anode of the electrolytic cell,it only needs a voltage of 1.5 V at the current density of 10 mA cm-2,and can keep stable for 60 h.This work provides a method for synthesizing transition metal compounds as bifunctional catalysts.3.A catalyst with small size and high activity for dehydrogenation of FA was synthesized by a simple impregnation-reduction method without adding surfactant.In the reaction process,weak base is used to regulate the pH value of the solution,which provides-conditions for the formation of small-sized alloy particles.By comparing the activity of a series of alloy catalysts with different ratios,the most suitable Ag and Pd ratios are found,and the TOF value of the optimal catalyst(Ag1Pd9/C)at 50? is 1331 h-1.The activation energy of AgiPd9/C is calculated to be 22.9 kJ mol-1.This work provides ideas for the synthesis of metal alloy nanoparticles with small size and uniform distribution.