Saha Sanjit, Mohan Das Gour
ENSEMBLE3 Centre of Excellence, Wolczynska 133, 01-919, Warsaw, Poland.
Chemphyschem. 2023 Nov 2;24(21):e202300526. doi: 10.1002/cphc.202300526. Epub 2023 Sep 1.
Nickel nanoparticle and graphene interfaces of various stoichiometries were created through electrodeposition techniques. The catalytic behavior of the electrodeposited films was investigated through spectro-electrochemical methodologies. UV-vis absorbance spectra of the electrodeposited films are significantly different in the air and alkaline medium. Furthermore, UV-vis and Raman spectroscopy confirmed the coupling of Ni nanoparticles (Ni-NP) with the graphene framework, along with NiO and Ni(OH) . A combination of Raman and impedance spectroscopy revealed that the surface adsorption and charge transfer properties of the electrodeposited films are entirely dependent on the defects on graphene structure as well as distribution of Ni-NP on graphene. The electrodeposited films possess heterogeneous catalytic properties with a low overpotential of 50 mV (10 mA/cm ) for hydrogen evolution reaction, as well as 601 mV and 391 mV (at 50 mA/cm ) for the oxygen evolution reaction and urea oxidation reaction, respectively. In addition, eelectrodeposited samples show extraordinary overall water splitting performance by achieving a current density of 10 mA/cm at a very low applied potential of 1.38 V. This synergistic coupling of Ni and graphene renders the electrodeposited samples promising candidates as electrodes for overall water splitting in alkaline and urea-supplemented solutions.
通过电沉积技术制备了具有不同化学计量比的镍纳米颗粒与石墨烯界面。采用光谱电化学方法研究了电沉积膜的催化行为。电沉积膜在空气和碱性介质中的紫外可见吸收光谱有显著差异。此外，紫外可见光谱和拉曼光谱证实了镍纳米颗粒（Ni-NP）与石墨烯骨架以及NiO和Ni(OH)的耦合。拉曼光谱和阻抗谱的结合表明，电沉积膜的表面吸附和电荷转移特性完全取决于石墨烯结构上的缺陷以及Ni-NP在石墨烯上的分布。电沉积膜具有异质催化性能，析氢反应的低过电位为50 mV（10 mA/cm²），析氧反应和尿素氧化反应在50 mA/cm²时的过电位分别为601 mV和391 mV。此外，电沉积样品在1.38 V的极低外加电位下实现了10 mA/cm²的电流密度，展现出优异的全水解性能。镍与石墨烯的这种协同耦合使电沉积样品有望成为碱性和添加尿素溶液中全水解电极的候选材料。
