Realizing efficient electrochemical overall water electrolysis through hierarchical CoP@NiCo-LDH nanohybrids

It is very important to design the catalysts with special spatial architectures and excellent electrochemical performance. It is well known that non-noble metal catalysts are inferior to Pt-like ones in electro-activity. However, their catalytic ability can be improved by the synergistic effect of different components. Herein, we synthesize several dendritic-like CoP@NiCo-LDH hetero-catalysts by a multi-step growth route. The CoP@NiCo LDH-100 samples present an overpotential of 225 mV @ 46.6 mV dec-1 for OER and 68.7 mV @ 74.03 mV dec- 1 for HER, which is superior to the commercial IrO2 (OER) and Pt/C (HER) in alkaline electrolyte. The density functional theory (DFT) calculation demonstrates that the composites possess low adsorption energy (1.11 eV) and tunable charge redistribution at the interface. An increased Fermi-level PDOS value proves the enhanced conductivity of the catalyst. The upward shift of the D-band center optimizes the desorption of the intermediates and accelerates the hydrolysis dissociation process. This increases the HER activity and thus reduces the overall electrolysis voltage.

Automated summary

It is crucial to design catalysts with unique spatial structures and excellent electrochemical performance. Although non-noble metal catalysts are less active than Pt-based ones, their catalytic ability can be enhanced by the synergistic effect of different components. In this study, several dendritic-like CoP@NiCo-LDH hetero-catalysts were synthesized using a multi-step growth route. The CoP@NiCo LDH-100 samples exhibited superior performance in OER and HER compared to commercial IrO2 (OER) and Pt/C (HER) in alkaline electrolyte. Density functional theory (DFT) calculation showed that the composites had low adsorption energy and tunable charge redistribution at the interface. The enhanced conductivity of the catalyst was confirmed by an increased Fermi-level PDOS value. The upward shift of the D-band center facilitated the desorption of intermediates and accelerated the hydrolysis dissociation process, leading to improved HER activity and reduced overall electrolysis voltage.