Synergetic regulation of CeO2 modification and (W2O7)2- intercalation on NiFe-LDH for high-performance large-current seawater electrooxidation

Four-electron process and the interference of Cl- make sluggish kinetics on oxygen evolution reaction (OER) for seawater electrolysis. Herein, NiFe LDH grown on NiFe-foam with CeO2 modification and (W2O7)2- intercalation was synthesized by one-step hydrothermal method. It only needs 353.8 and 386.7 mV to achieve a large current density of 1000 mA·cm−2 in 1 M KOH and alkaline natural seawater, respectively. The catalytic material can stand 100 h with a retention of 98.1% at 1000 mA·cm−2 in alkaline natural seawater. Experiments and theoretical calculations confirm that the state-of-the-art OER activity comes from the introduced CeO2 with optimized adsorption energy of intermediates. The improved stability and selectivity in seawater can be ascribed to the preferential adsorption of Ni and Fe with higher valence on OH- based on hard and soft acid based (HSAB) principle by (W2O7)2- intercalation. This work provides a viable approach to develop efficient catalytic material for large-current seawater electrolysis. NiFe LDH nanosheets with (W2O7)2- intercalation and CeO2 modification show state-of-the-art large-current seawater-electrooxidation performance contributed partially from introduced CeO2 adjusting adsorption energy of intermediates during OER process, partially from preferential adsorption of OH- on metal active sites based on hard and soft acid based (HSAB) principle by (W2O7)2- intercalation. [Display omitted] •NiFe LDH nanosheets with (W2O7)2- intercalation and CeO2 modification have been successfully synthesized.•It only needs an overpotential of 386.7 mV to achieve 1000 mA cm−2 in alkaline natural seawater electrocatalysis.•(W2O7)2- intercalation enhances OH- selectivity and CeO2 modification optimizes adsorption energy towards OER intermediates.