一种菜花状Co_(3.2)Fe_(0.8)N/Ir双功能电催化剂用于酸性介质水分解

Cauliflower-like Co_(3.2)Fe_(0.8)N/Ir nanocomposite as the bifunctionalelectrocatalyst for water splitting in acidic medium

在酸性介质中,寻找具有优良析氧(OER)和析氢反应(HER)双功能活性且稳定的电催化剂面临着巨大的挑战.本文中通过NaBH_(4)共还原结合氮化法制备一系列Co_(3.2)Fe_(0.8)N/Ir材料,其结构为Co_(3.2)Fe_(0.8)N纳米薄片负载Ir微粒而成的菜花状多孔复合体.其中,Co_(3.2)Fe_(0.8)N/Ir-42(Ir%=41.8,wt)催化剂具有最优的HER/OER双功能活性,在0.5 mol/L H_(2)SO_(4)中及10 mA/cm^(2)下HER超电势仅为16.6 mV,超过了商业Pt/C(Pt%=20,wt)标准催化剂;OER超电势为321 mV,接近IrO_(2)基准.此外,该催化剂对HER及OER的稳定性均明显高于商业Pt/C与IrO_(2)基准催化剂,将其用于整体水分解反应阴阳极材料时,获得10 mA/cm^(2)电流密度仅需要1.545 V的电解电压.

Searching the cost-effective and robust electrocatalysts with excellent bifunctional activity for oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)toward overall water splitting in acidic medium is of great challenge.Here,we report a series of Co_(3.2)Fe_(0.8)N/Ir nanocomposites prepared through a facile co-reduction assisted nitridation method which are the Ir particles deposited on the Co_(3.2)Fe_(0.8)N nanosheets.Among them,the Co_(3.2)Fe_(0.8)N/Ir-42(Ir%(wt)=41.8)catalyst exhibits the outstanding OER/HER activities in 0.5 mol/L H_(2)SO_(4) solution with an HER overpotential of 16.6 mV at 10 mA cm^(-2) surpassing the commercial Pt/C(Pt%(wt)=20),and an OER overpotential of 321 mV at 10 mA cm^(-2) similar with the IrO_(2) benchmark.Moreover,Co_(3.2)Fe_(0.8)N/Ir-42 demonstrates commendably higher stability than Pt/C for HER and superior long-time durability than IrO_(2) benchmark for OER in acidic electrolyte.It also exhibits the expected performance for overall water splitting which just needs the cell voltage of 1.545 V to afford a current density of 10 mA/cm^(2).