Metalloenzyme-Inspired Cluster Fabrication within Mesoporous Channels Featuring Optimized Catalytic Microenvironments for Efficient Neutral pH HO Electrosynthesis.

In nature, some metalloenzymes facilitate highly efficient catalytic transformations of small molecules, primarily attributed to the effective coupling between their metal cluster active sites and the surrounding microenvironment. Inspired by this, a thermotropic redispersion strategy to incorporate bismuth nanoclusters (Bi NCs) into mesoporous channels, mimicking metalloenzyme-like catalysis to enhance the two-electron oxygen reduction reaction (2e ORR) for efficient neutral pH HO electrosynthesis, is developed. This model electrocatalyst exhibits exceptional 2e ORR performance with >95% HO selectivity across 0.2-0.6 V vs RHE in neutral electrolyte. Notably, the system produces up to 7.2 wt% neutral HO solution at an industrially relevant current density of ≈320 mA cm, with 90% Faradaic efficiency for HO over 120 h in a flow cell, demonstrating significant practical potential. Mechanistic insights reveal that the introduction of Bi NCs enhances the adsorption of the *OOH intermediate, facilitating a highly active 2e ORR process. Moreover, the mesoporous channels of the carbon support create a favorable catalytic microenvironment for O aeration and local alkalinity, further boosting HO productivity. This catalyst design mimics metalloenzymes by optimal integration of the active site with the surrounding microenvironment, offering valuable insights for the rational design of nature-inspired small-molecule catalysts.