Modification of NiFe layered double hydroxide by lanthanum doping for boosting water splitting

Electrolysis of water can directly produce hydrogen and oxygen, providing the possibility to expand the production of high purity hydrogen. It consists of two half reactions: anodic oxygen evolution reaction (OER) and cathodic hydrogen evolution reaction (HER). Developing electrocatalysts is an effective way to improve the efficiency of water splitting. Two-dimensional layered double hydroxides (LDHs), as abundant, cheap and bifunctional catalysts, have the similar electrocatalytic performance as precious metals, thereby receiving pretty much attention. Here, a facile flash nano-precipitation (FNP) synthetic strategy is presented to acquire NiFe LDH. Based on it, La-NiFe LDH is obtained by adding rare earth element lanthanum (La) with different contents using mechanical method. Owing to the synergistic effect between La and laminate metal, La-NiFe LDH shows an excellent water splitting performance, where the overpotential of OER activity is 340 mV and HER performance is 57 mV at the current density of 10 mA∙cm−2. Combined with characterization, performance and theoretical calculation, it is confirmed that the electronic structure of LDH laminates can be adjusted by La doping, reducing the Gibbs free energy in the reaction accordingly, which is beneficial to the water splitting reaction. In general, an easy-to-implement and rapid preparation method provides a convenient and green way to obtain water splitting catalyst with enhanced performance.