Preparation Of Low/Non-precious Metal Electrocatalysts And Their Performance In The Electrolysis Of Water

The world is currently in the era of rapid changes and advanced technology,with all walks of life in the flourishing development of the same time,transportation is indispensable as a carrier to support circulation.With the increasing share of energy consumption dominated by transportation in the total energy consumption,the shortag e of traditional energy resources leads to energy depletion,and the continuous increase of carbon emissions leading to the greenhouse effect.The marketisation of fuel cells by 2035 is one of the plans for the development of the new energy vehicle industr y.Fuel cells using hydrogen as fuel are considered to be the best alternative to internal combustion engines,making hydrogen energy a hot research topic as the"future energy".As electrolysis of water is one of the effective ways to obtain hydrogen,it has triggered researchers to explore the corresponding HER and OER catalysts to achieve lower energy consumption and accelerate the reaction.The current commercial catalysts are precious metal-based materials,which cannot be popularised due to low economic benefit and unsustainable performance.The development of low/non-precious metal based catalysts is therefore essential.Two structures were designed in this paper,namely,ZIF-8-derived nitrogen-doped carbon porous structures with restricted domain ultra-small Pt atoms/clusters as HER catalysts and PPy-derived nitrogen-doped carbon nanotube-loaded and encapsulated iron-cobalt alloy structures as OER catalysts.（1）Constructing ZIF-8 nanocrystal-coated Zn O nanorod arrays structures by hydrothermal and in situ ion exchange methods,which can pro vide large active surface areas,and the structures of nitrogen-doped porous carbon restricted Pt atoms/clusters were formed by simple impregnation adsorption method and high-temperature calcination,and the synergistic effects of the small size effect of precious metal Pt,restricted structure and N-doping enabled the prepared CTAs@Pt@NCBs sample to have excellent HER catalytic performance.Theη₁₀ in acidic electrolyte is 27.42 m V,which is lower than the commercial Pt/C of 36.43 m V,and has a low tafel value of 37.5m V dec^-1,where the Volmer-Heyrovsky reaction mechanism occurs.After 60 h of CP test,the potential retention rate was 97.18%,which showed excellent stability.（2）Using molybdenum trioxide as a sacrificial template,PPy is formed by chemically oxidizing polymerized Py to uniformly coat the molybdenum trioxide surface,and then alkaline etching to form hollow PPy nanotubes as a carrier for iron-cobalt alloy,which not only provides a large-area carrier,but also serves to encapsulate iron-cobalt alloys.By exploring the samples with different molar ratios of Fe and Co,it is concluded that the ratio of 1:1 has the best OER performance.Thanks to the N-doping and packaging structure,theη₁₀ of Fe_0.5Co_0.5/N-CNTs in alkaline electrolyte is230 m V,which is lower than that of commercial Ru/C at 490 m V,and has a lower tafel value of 94.5 m V dec^-1.After 10 h of CA test,the current retention rate of Fe_0.5Co_0.5/N-CNTs is 73.17%,which is 5.09 times of commercial Ru/C,showing good stability.