Preparation And Study Of Non-noble-metal Catalysts For The Electro-reduction Of Carbon Dioxide And Water Splitting

In order to solve the regional and intermittent problems of renewable energy,the transformation between electric energy and chemical energy through electrochemistry will play an important role.Among all kinds of conversion technologies between chemical energy and electrical energy,electro-catalytic reduction of carbon dioxide and water electrolysis can obtain "clean fuel",which will have a revolutionary significance on environment and energy.This paper focuses on the preparation and exploration of non-precious metal catalysts used in carbon dioxide reduction and water electrolysis reaction.The main results are as follows:1.A series of CoxCu1-xO as carbon dioxide reduction catalysts were prepared by different synthetic methods.Precipitated by NaOH,Co0,5Cu0.5O had an initial potential of-0.83 V(vs.SCE)and a peak current density of-2.71 mA/cm2 in the CO2-saturated electrolyte.The study found that cobalt and copper in CoxCu1-xO catalysts showed excellent synergistic effect.2.The catalytic ability of Co(OH)2 toward carbon dioxide reduction reaction(CO2RR)was discovered.Iron was introduced during the preparation to form 200 nm spinel cube CoFeOx(CFO),in which Co2+is the active site and Fe3+ is for stabilizing.CFO had an initial potential of-0.80 V(vs.SCE)and a peak current density of-0.58 mA/cm2,and it can keep good stability within 15 hours.The main products were acetone and methanol.3.The catalytic performance of CoOxfor oxygen evolution reaction(OER)was optimized through adjusting the varieties and amounts of the surfactant used during the preparation.Adding neutral PVP leads to a better performance with an overpotential only about 378 mV at 10 mA/cm2 than adding anionic hexadecyl sulfonate(421 mV).Connecting the different Co2+/Co3+ ratio controlled by the concentration of ascorbic acid with OER catalytic activity of CoOx,we find that the OER performance of CoOx was enhanced with the increase of Co2+ content,which indicates Co2+ should be responsible for the electrocatalytic activity of CoOx.CoOx-P2V0.3 is a stable and highly effective OER catalyst.The overpotential is only 352 mV at 10 mA/cm2,and the activity is almost unattenuated in 10 h,exhibiting good application prospect.4.We designed a rhombic dodecahedron Co@Co3O4-NC with a simple method,which catalyzed HER in neutral electrolyte(pH-7)with an overpotential of 610 mV at 10 mA/cm2,and afterl2-hour electrolysis the current density decreased only 13%,more stable than Pt/C.