Synergistic promotion of HER and OER by alloying ternary Zn‐Co‐Ni nanoparticles in N‐doped carbon interfacial structures

界面N-C负载三元Zn-Co-Ni合金纳米材料对电催化水分解的协同增强效应

Catalytic water splitting potentially reduce the consumption of fossil fuels and has received intense research attention.Synergy effects in multi‐element transition metal‐based water splitting catalysts have evoked special interests.Studies on catalysts in interfacial structures are especially meaningful due to their pertinence in applications.In this study,we report the synergy effects in promoting catalytic power in the ternary transition metal Zn,Co,Ni alloy nanoparticles that embeds in the carbonized Ppy/CNT multilayered matrix.By comparison with a series of binary or single metal counterparts,the mechanism under the synergy effects are elucidated.Experimental and DFT calculation results indicate that the ternary transition metal catalysts in the N‐doped carbon matrix present special electronic structure,which benefits the reversible transition‐state adsorption in HER and OER and render the catalysts high conductivity in room temperature.We expect our findings inspire further development of efficient transition metal HER and OER catalysts.

电催化水分解制氢能够减少化石燃料的消耗,克服可再生太阳能和风能间歇性的缺点,在能源转换技术中具有巨大的应用前景,并受到研究人员的广泛关注.过渡金属基材料是最有前途的非贵金属电解水催化剂.人们致力于通过各种方法,如掺杂、结构工程或生成缺陷,以提高过渡金属基催化剂的催化能力.由于大多数电催化剂用于电极表面,研究界面多元素催化剂在相应基体中的催化行为和机理变得尤为重要.近年来,多组分过渡金属基电解水催化剂的协同效应引起了科学家的兴趣.研究者在三元镍-钨-铜合金和过渡金属氧化物等材料体系中观察到催化剂活性随着组分种类的增加而增强.高性能电解水催化材料的开发仍需要对多金属催化剂的机理进行深入的研究.本文采用金属电沉积制备了嵌入在碳化Ppy/CNT基底中的三元过渡金属Zn-Co-Ni合金纳米粒子,研究了其在提升电解水催化能力方面的协同增强效应.通过与一系列的一元或二元金属催化剂的比较,析氢反应(HER)和析氧反应(OER)性能随着组分多样性的增加而增强,并阐明了协同效应下的机制.结果表明,三元金属催化剂ZnCoNi/(Ppy/CNTs)_(4)具有最佳的HER和OER催化效率.DFT模拟计算显示ZnCoNi/(Ppy/CNTs)_(4)催化剂中的电子转移显著改变,降低了HER和OER过渡态的能垒,并增加了活性位点的数量.同时ZnCoNi/(Ppy/CNTs)_(4)催化剂的态密度刚好高于费米能级,界面电子转移电阻小,使催化剂在室温下具有高导电性,同时有利于HER和OER中的可逆过渡态物质的吸附.本研究对高效过渡金属基HER和OER催化剂的进一步开发有一定的启发作用.