双金属氮化物Co3W3N/CNTs纳米复合材料的制备及其室温常压氮还原性能

采用水热法并经氨气保护热处理制备了双过渡金属氮化物Co3W3N/CNTs复合材料,得到了价格低廉且拥有良好氮电化学还原性能(NRR)的催化剂。通过调节已经预氧化的CNTs与过渡金属氮化物前驱体CoWO4的比例以及氨气热处理温度,实现了Co3W3N在CNTs表面的均匀负载。扫描电子显微镜(SEM)及透射电子显微镜(TEM)测试结果显示该电化学活性纳米微粒均匀地分散于CNTs表面,表明经预氧化的CNTs由于表面富集了较多的活性基团,有利于双过渡金属氮化物的分散生长。热处理后CNTs表面的Co3W3N微粒尺寸约为20 nm,相较于无载体的Co3W3N尺寸(100 nm)有明显减小。室温条件下,在N2饱和的0.01 mol·L^-1 H2SO4溶液中测试了该纳米复合材料在不同过电位下的NRR,该材料在-0.3 V(vs RHE)时的产氨率及法拉第效率分别可达12.73μg·h^-1·cm-2和13.59%,对比同样条件下,纯相Co3W3N的产氨率及法拉第效率仅为1.08μg·h^-1·cm^-2和1.76%。结果表明,通过水热反应和氨气保护热处理的Co3W3N/CNTs纳米复合材料具有良好的NRR性能。

Carbon Nanotube-Based Bimetallic Nitride Co3W3N for Electrocatalytic Synthesis of Ammonia under Ambient Condition

A kind of cheap carbon nanotube-based double transition metal nitrides Co3W3N/CNTs composite was prepared by hydrothermal and subsequent heat treatment under ammonia.By adjusting the proportion the of pre oxidation of CNTs and precursor CoWO4 and ammonia heat treatment temperature,the Co3W3N in uniform load on the surface of the CNTs.Scanning electron microscopy(SEM)and transmission electron microscope(TEM)test results showed that the catalyst particles evenly dispersed on the surface of CNTs,due to oxidation CNTs for the good dispersion growth of precursor.The Co3W3N particle size on the CNTs was about 20 nm,which was significantly smaller than that of unsupported Co3W3N(100 nm).The electrochemical tests was carried out in a N2 saturated 0.01 mol·L-1 H2SO4 solution under different potential,and the material achieved the highest ammonia production rate and Faraday efficiency at-0.3 V,which reached approximately 12.73μg·h^-1·cm^-2 and 13.59%,respectively.Under the same conditions,the ammonia production rate and Faraday efficiency of pure phase Co3W3N were only 1.08μg·h-1·cm^-2 and 1.76%.The Co3W3N/CNTs sample showed excellent NRR(nitrogen reduction reaction)performance because of the Co3W3N as the active site and the synergistic effect of Co3W3N and CNTs.