Ru-Doping and Conductive Metal-Organic-Frameworks Co-Modification Strategy for Enhanced Full Water Splitting Performance of CoCu-LDH Nanosheets Array

It has been attracting extensive research interest how to promote the electrocatalytic performance of transition-metal layered double hydroxides (LDHs) for water splitting. Here, we designed a heteroatom-doping and conductive metal-organic frameworks (cMOFs) co-modification strategy to successfully construct a Ru-doped CoCu-HHTP (HHTP=2,3,6,7,10,11-hexahydroxytriphenylene) /CoCu-LDH nanosheets array on the Cu foam substrate (labeled as CoCuRu-HHTP/CoCu-LDH). Electrochemical measurements showed that CoCu-LDH, CoCuRu-LDH, CoCu-HHTP/CoCu-LDH and CoCuRu-HHTP/CoCu-LDH separately required an overpotential of 204 mV, 175 mV, 69 mV, 27 mV to deliver the current density of -10 mA cm-2 for HER; and 345 mV, 216 mV, 275 mV, 204 mV to reach the current density of 10 mA cm-2 for OER; in 1 M KOH solution. The above facts clearly demonstrate that the present co-modification strategy significantly enhances the electrocatalytic water splitting performance of CoCu-LDH. In a two-electrode setup using the as-prepared CoCuRu-HHTP/CoCu-LDH nanosheets array as the cathode and anode simultaneously, only a cell voltage of 1.48 V was required to deliver the current density of 10 mA cm-2, which is comparable to that of pure noble metal-based materials and outperforms most MOF-based catalysts reported.