Boosting of overall water splitting activity by regulating the electron distribution over the active sites of Ce doped NiCo-LDH and atomic level understanding of the catalyst by DFT study

Electrolysis of water plays a vital role in the generation of hydrogen as compared to the other methods such as hydrolysis of metal hydrides, steam reforming, coal gasification, and oxidation of methane gas. All those methods have several disadvantages, and hence, the development of efficient electrocatalysts with low cost and long stability towards water electrolysis for solving the energy crisis is needed. An LDH material is an efficient candidate for the OER process but not as efficient for the HER process. Here, in this study, the doping of Ce3+ over NiCo-LDH/NF modulates the electronic structure of the active metal sites, enhancing the performance of both OER and HER processes and affecting the microstructure, electrocatalytic performance, and electronic structure of NiCo-LDH/NF. In OER and HER, the catalyst Ce@NiCo-LDH demanding overpotential values of 250 mV and 134 mV to attain a current density of 50 mA cm(-2) and Tafel slope values of 98 and 98.6 mV dec(-1), respectively. Furthermore, the overall water splitting was carried out by a chronoamperometric study for Ce-doped NiCo-LDH/NF showing electrochemical performance for 36 h with the current density at 10 mA cm(-2) at 1.68 V vs. RHE. A DFT study at the atomic level of pristine and Ce doped NiCo-LDH revealed that the doping of Ce improves the electronic conductivity of the catalyst, and Co-3d states dominate the water splitting activity as compared to other Ni-3d and Ce-4f states. This work provides an alternate route to design a highly efficient and cost effective catalyst for global clean energy production.

Automated summary

In this study, Ce3+ doping of NiCo-LDH was found to enhance the performance of both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The doping of Ce improved the electronic conductivity of the catalyst and Co-3d states played a dominant role in water splitting activity. This work provides an alternate route to design a highly efficient and cost effective catalyst for global clean energy production.