School of Materials Science and Engineering, State Key Laboratory of Marine Resource Utilization of South China Sea, Hainan University, Haikou 570228, China.
Nanoscale. 2019 Feb 14;11(7):3378-3385. doi: 10.1039/c8nr09740b.
Electrochemical water splitting requires an efficient water oxidation catalyst to accelerate the oxygen evolution reaction (OER). A triple hierarchy catalyst structure based on abundant transition metals in soil (Fe, Co, and Ni) was prepared via chemical bath deposition, followed by a hydrothermal and electrodeposition method for the high-efficiency OER. The obtained electrode consisted of a three-layer porous structure, with a carbon cloth (CC) substrate as the bottom layer, vertically aligned Co9S8 nanotubes as the intermediate layer, and NiFe hydroxide as the top layer, resulting in two synergistic effects between Co9S8 and CC, and NiFe and Co9S8. This layered structure contained no binder, which facilitated catalytic site exposure, enhanced electron transfer, and accelerated the dissipation of gases generated during the catalytic process. This triple hierarchy multimetal/carbon electrode exhibited remarkable OER activity in an alkaline medium with a small overpotential of 219 mV (vs. RHE) at 10 mA·cm-2 and low Tafel slope of 55 mV·dec-1. Furthermore, this triple hierarchy electrode was stable for up to 20 h. The prepared triple hierarchy polymetallic material can be considered to be among the most promising oxygen evolution catalysts.
电化学水分解需要高效的水氧化催化剂来加速氧气析出反应 (OER)。通过化学浴沉积法，然后采用水热和电沉积法，制备了一种基于土壤中丰富的过渡金属（Fe、Co 和 Ni）的三重层次催化剂结构，用于高效的 OER。所得到的电极由三层多孔结构组成，以碳纤维布 (CC) 为底层，垂直排列的 Co9S8 纳米管为中间层，NiFe 氢氧化物为顶层，这导致了 Co9S8 和 CC 之间以及 NiFe 和 Co9S8 之间的两种协同效应。这种分层结构不含粘结剂，有利于催化位点暴露、增强电子转移并加速催化过程中产生的气体的耗散。这种三重层次多金属/碳电极在碱性介质中表现出显著的 OER 活性，在 10 mA·cm-2 时的过电势仅为 219 mV（相对于 RHE），塔菲尔斜率低至 55 mV·dec-1。此外，这种三重层次电极稳定长达 20 小时。所制备的三重层次多金属材料可以被认为是最有前途的氧气析出催化剂之一。
