Room-temperature synthesis of NiFe-hexamethylenetetramine as lattice oxygen involved electrocatalyst for efficient oxygen evolution reaction.

The design and synthesis of an oxygen evolution reaction (OER) electrocatalyst following lattice oxygen mechanism (LOM) through a straightforward strategy is crucial for achieving efficient electrocatalytic hydrogen production; however, it remains a formidable challenge. Herein, a novel and highly efficient LOM-based OER electrocatalyst, NiFe-hexamethylenetetramine (NiFe-HMT) coordination compound, is fabricated through a straightforward co-precipitation strategy at room temperature within 30 min. The obtained NiFe-HMT exhibits remarkable OER activity with low overpotentials of 269 and 352 mV to achieve 100 and 1000 mA cm, respectively. Experimental results and theoretical calculations reveal that the incorporation of Fe can effectively activate the lattice oxygen in the reconstructed oxyhydroxides, thereby shifting the OER pathway from adsorbate evolution mechanism to LOM. Additionally, compared with NiFe-LDH, NiFe-HMT is more favorable for forming highly active oxyhydroxides and exhibits more significant lattice oxygen activity. Furthermore, NiFe-HMT can be scaled up to more than 10 g in a single batch and stored stability for over 142 days without any significant decline in activity, thereby indicating its potential for large-scale implementation. This study provides valuable insights into developing high-performance OER electrocatalysts following the LOM pathway.