Lattice‐Matching Formed Mesoporous Transition Metal Oxide Heterostructures Advance Water Splitting by Active Fe–O–Cu Bridges

• Published in: Advanced energy materials 2022-05, Vol.12 (19), p.n/a
• Main Authors: Hu, Feng, Yu, Deshuang, Ye, Min, Wang, Hui, Hao, Yanan, Wang, Luqi, Li, Linlin, Han, Xiaopeng, Peng, Shengjie
• Format: Article
• Language: English
• Subjects: Accessibility; Catalysis; Catalysts; Copper; electrocatalysis; Electrocatalysts; heterostructure; Heterostructures; Hydrogen evolution reactions; Hydrogen production; Iron; Lattice matching; Mass transport; mesoporous structures; Oxygen evolution reactions; Transition metal oxides; Water splitting
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202200067

Developing efficient bifunctional electrocatalysts toward oxygen/hydrogen evolution reactions is crucial for electrochemical water splitting toward hydrogen production. The high‐performance electrocatalysts depend on the catalytically active and highly accessible reaction sites and their structural robustness, while the rational design of such electrocatalysts with desired features avoiding tedious manufacture is still challenging. Here, a facile method is reported to synthesize mesoporous and heterostructured transition metal oxides strongly anchored on a nickel skeleton (MH‐TMO) containing identified Fe–Cu oxide interfaces with high intrinsic activity, easy accessibility for reaction intermediates, and long‐term stability for alkaline oxygen/hydrogen evolution reactions. The MH‐TMO with the electrocatalytically active Fe–O–Cu bridge has an optimal oxygen binding energy to facilitate adsorption/desorption of oxygen intermediates for oxygen molecules. Associated with the high mass transport through the nanoporous structure, MH‐TMO exhibits impressive oxygen evolution reaction catalysis, with an extremely low overpotential of around 0.22 V at 10 mA cm−2 and low Tafel slope (44.5 mV dec−1) in 1.0 M KOH, realizing a current density of 100 mA cm−2 with an overpotential as low as 0.26 V. As a result, the alkaline electrolyzer assembled by the bifunctional MH‐TMO catalysts operates with an outstanding overall water‐splitting output (1.49 V@10 mA cm−2), outperforming one assembled with noble‐metal‐based catalysts. A facile method based on a lattice‐matching strategy is reported to synthesize Fe–Cu oxides with high mesoporosity and unique heterostructure. The established structure possesses high activity for the oxygen evolution reaction with an extremely low overpotential of around 0.22 V at 10 mA cm−2 as well as electrocatalytic bifunctionality for high‐performance water splitting with an outstanding overall output (1.49 V@10 mA cm−2).