| The history of energy evolution in the past century is essentially the history of adjustment of hydrocarbon ratio.Increasing hydrogen content increases the energy density.Therefore,the future transition to hydrogen energy is the general trend of historical development and social progress,and hydrogen energy is expected to become the next generation of basic energy.It is well known that electrocatalytic hydrogen production is considered to be a very effective way to produce hydrogen,and the limiting hydrogen production efficiency is the oxygen generation semi-reaction(OER).This short-board problem has aroused widespread concern in the scientific community.Moreover,the method of preparing the OER electrode by the drop coating method also limits the improvement of the catalytic performance.In recent years,emerging nano-array materials and metal-organic framework(MOF)derivatives have brought us the dawn of solving this problem,combining the two advantages of MOF derivatives and nano-arrays to solve the above-mentioned problems.Very important meaning.In this paper,through two simple and rapid synthesis and transformation methods,the ordered nano-array MOF materials were obtained firstly.Finally,the derivative nano-array electrodes were obtained by a series of methods,and their electrochemical properties were studied.The main research contents and conclusions are as follows:1.A Mn-MOF nano-array electrode was successfully prepared on a foamed nickel substrate by hydrothermal method.The Mn O/C nanorod array was obtained by calcination in an inert gas.This is the first case obtained by using Mn-MOF nano-array as a sacrificial template.Work on Mn O/C nanoarrays.In addition,we also studied the effect of calcination of precursors on OER performance at different temperatures.It was found that the electrode material obtained by Mn O/C nanorod array at 350?showed excellent oxygen evolution catalytic performance.When the current density was 20 m A cm-2,the required overpotential was only 329 m V(V vs RHE).The excellent OER catalytic performance is attributed to the difference in carbon content retention of MOF derivatives at different temperatures,thus enhancing the conductivity of the material electrode,improving the utilization of electrons,and retaining its unique neatly ordered nanorod array structure.And the surface morphology increases the electrochemical surface area and also makes the cycle stability stronger,which has a great influence on improving the overall catalytic performance of OER.Therefore,it can be concluded that the preparation of derivative nanoarrays by MOF array is effective and feasible for enhancing the oxygen evolution reaction.2.On the three-dimensional foam nickel substrate,MOF nanorod array(Mn-MOF-74)was prepared as precursor,and Mn2O3nanotube array(Mn2O3NAs)electrode was obtained by temperature-controlled annealing in air atmosphere.The research showed that it was in 1.0 M KOH solution.With a lower overpotential of 270 m V,the current density of 10 m A cm-2can be achieved.The corresponding Tafel slope is only 85 m V dec-1and the Faraday efficiency is close to100%.In addition to excellent OER performance,Mn2O3NAs also exhibit an increased specific capacitance(677 F g-1)at 1 m A cm-2,and most of the reported Mn2O3materials are preferred.The excellent electrocatalytic effect proves intuitively that the electrode preparation method is an essential factor for improving OER performance and increasing specific capacitance.3.Using the foamed nickel substrate as the metal source,the ultrathin nanosheet Ni-(TCNQ)2·(H2O)2(TCNQ:tetracyanate)was synthesized by low temperature hydrothermal method,and the derivative Ni O was obtained by electrolytic oxidation.Both Ni-(TCNQ)2·(H2O)2and Ni O-TCNQ exhibit amazing OER catalytic properties.At a current density of 100 m A cm-2,the overpotentials are 490 m V and 359 m V,respectively.The Tafel slope of Ni O-TCNQ is only57.95 m V dec-1,and the Faraday efficiency is close to 100%.4.The Prussian blue nanocube array precursor(PB,Fe4[Fe(CN)6]3)was synthesized on the conductive substrate by one-step hydrothermal method,and the derivative Fe2O3mesoporous nanocube array was obtained by high temperature oxidation.And constructing double metal hydroxide and oxide nano-array on the surface of Fe2O3nanocube array,and studying its relationship between the improvement of OER performance and metal species.Experimental data show that hydroxide and oxidation of cobalt and nickel are two elements.The materials were loaded in situ with PB and ferric oxide cube nano-array.The Ni(OH)2supported on the surface of PB and Fe2O3had the best catalytic performance for OER,which indicated that the metal synergy of nickel and iron was the most significant. |
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