Preparation Of Manganese Oxide Electrocatalysts And Their Electrocatalytic Performanc

To improve the traditional energy structure and achieve the great goal of’carbon neutrality’,researchers have developed a series of strategies to improve the hydrogen production efficiency of electrolytic water.In this paper,heteroatom doping and defect engineering strategies are mainly used to improve the intrinsic activity of electrocatalysts.By constructing a new（formaldehyde/glycerol/urea-based）electrolytic cell,the hydrogen production efficiency and the energy conversion efficiency of the electrolytic cell are further improved.（1）S-dopedα-MnO₂（S-MnO₂）nanowires are synthesized by a simple hydrothermal method.In alkaline electrolyte,S-MnO₂ exhibits higher oxygen evolution reaction（OER）activity than MnO₂.When the overpotential is 600 m V,the OER current density value is 4.75times that of MnO₂,S doping provides more Mn³⁺active sites,oxygen vacancies（V_O）and electrochemical active surface area.Theoretical calculations further confirm that V_O leads to higher surface energy of S-MnO₂,which is beneficial to the adsorption of H₂O and OH^-at Mn³⁺sites.In addition,the formaldehyde-based electrolytic cell is constructed.Compared with the traditional electrolytic cell,the Faradic efficiency of hydrogen production is increased from89.6%to 98.6%,and the cell voltage required for the formaldehyde-based electrolytic cell is reduced by about 17.17%at a current density of 100 m A cm^-2.At the same time,52%of formaldehyde is degraded after running at 1.75 V for 2 h.The results show that the new electrolytic cell can not only greatly improve the efficiency of hydrogen evolution,but also efficiently degrade formaldehyde pollutants.（2）Ultrathin birnessite nanosheets@nickel foam array（KMO@NF）electrocatalysts are synthesized by in-situ growth method.KMO@NF exhibits excellent electrolytic water activity due to the abundant V_O and Mn³⁺on its surface.In addition,a glycerol/urea-based electrolytic cell is constructed.Compared with OER,the corresponding anode current density is increased by 19.34 and 18.04 times at 1.43 V,respectively.The Faradic efficiency of hydrogen production reaches 95%and 97%,respectively,which proves that the designed electrolytic cell had higher energy conversion rate.This study provides practical ideas for the selection of efficient electrocatalysts and the design of new electrolytic cell.