Electrocatalytic reduction of oxygen is a growing synthetic technique for the sustainable production of hydrogen peroxide(H_(2)O_(2)).The current challenges concern seeking low-cost,highly active,and selective electro...Electrocatalytic reduction of oxygen is a growing synthetic technique for the sustainable production of hydrogen peroxide(H_(2)O_(2)).The current challenges concern seeking low-cost,highly active,and selective electrocatalysts.Cobalt-nitrogen-doped carbon containing catalytically active cobalt-nitrogen(Co-N_(x))sites is an emerging class of materials that can promote the electrochemical generation of H_(2)O_(2).Here,we report a straightforward method for the preparation of cobalt-nitrogen-doped carbon composed of a number of Co-N_(x)moieties using low-energy dry-state ball milling,followed by controlled pyrolysis.This scalable method uses inexpensive materials containing cobalt acetate,2-methylimidazole,and Ketjenblack EC-600JD as the metal,nitrogen,and carbon precursors,respectively.Electrochemical measurements in an acidic medium show the present material exhibits a significant increase in the oxygen reduction reaction current density,accompanied by shifting the onset potential into the positive direction.The current catalyst has also demonstrated an approximate 90%selectivity towards H_(2)O_(2)across a wide range of potential.The H_(2)O_(2)production rate,as measured by H_(2)O_(2)bulk electrolysis,has reached 100 mmol g_(cat).^(–1)h^(–1)with high H_(2)O_(2)faradaic efficiency close to 85%(for 2 h at 0.3 V vs.RHE).Lastly,the catalyst durability has been tested(for 6 h at 0.3 V vs.RHE).The catalyst has shown relatively consistent performance,while the overall faradic efficiency reaches approximate 85%throughout the test cycle indicating the promising catalyst durability for practical applications.The formed Co-N_(x)moieties,along with other parameters,including the acidic environment and the applied potential,likely are the primary reasons for such high activity and selectivity to H_(2)O_(2)production.展开更多
文摘Electrocatalytic reduction of oxygen is a growing synthetic technique for the sustainable production of hydrogen peroxide(H_(2)O_(2)).The current challenges concern seeking low-cost,highly active,and selective electrocatalysts.Cobalt-nitrogen-doped carbon containing catalytically active cobalt-nitrogen(Co-N_(x))sites is an emerging class of materials that can promote the electrochemical generation of H_(2)O_(2).Here,we report a straightforward method for the preparation of cobalt-nitrogen-doped carbon composed of a number of Co-N_(x)moieties using low-energy dry-state ball milling,followed by controlled pyrolysis.This scalable method uses inexpensive materials containing cobalt acetate,2-methylimidazole,and Ketjenblack EC-600JD as the metal,nitrogen,and carbon precursors,respectively.Electrochemical measurements in an acidic medium show the present material exhibits a significant increase in the oxygen reduction reaction current density,accompanied by shifting the onset potential into the positive direction.The current catalyst has also demonstrated an approximate 90%selectivity towards H_(2)O_(2)across a wide range of potential.The H_(2)O_(2)production rate,as measured by H_(2)O_(2)bulk electrolysis,has reached 100 mmol g_(cat).^(–1)h^(–1)with high H_(2)O_(2)faradaic efficiency close to 85%(for 2 h at 0.3 V vs.RHE).Lastly,the catalyst durability has been tested(for 6 h at 0.3 V vs.RHE).The catalyst has shown relatively consistent performance,while the overall faradic efficiency reaches approximate 85%throughout the test cycle indicating the promising catalyst durability for practical applications.The formed Co-N_(x)moieties,along with other parameters,including the acidic environment and the applied potential,likely are the primary reasons for such high activity and selectivity to H_(2)O_(2)production.
