Regulating the electronic structure of Ir single atoms by ZrO2 nanoparticles for enhanced catalytic oxidation of formaldehyde at room temperature

Developing low-loading single-atom catalysts with superior catalytic activity and selectivity in formaldehyde (HCHO) oxidation at room temperature remains challenging. Herein, ZrO2 nanoparticles coupled low-loading Ir single atoms in N-doped carbon (Ir1-N-C/ZrO2) was prepared. The optimal Ir1-N-C/ZrO2 with 0.25 wt% Ir loading delivers the high HCHO removal and conversion efficiency (> 95%) at 20°C, which is higher than that over Ir1-N-C with the same Ir loading. The specific rate can reach 1285.6 mmol·gIr−1·h−1, surpassing the Ir based catalysts reported to date. Density functional theory calculation results and electron spin resonance spectra indicate that the introduction of ZrO2 nanoparticles modulate the electronic structure of the Ir single atoms, promoting O2 activation to •O2–. Moreover, the Ir-C-Zr channel is favorable for the dissociation of •O2– to active oxygen atom (*O), and further accelerates the transformation of HCHO and intermediates (dioxymethylene and formates) to CO2 and H2O. This work provides a facile strategy to design low-loading single-atom catalysts with high catalytic activity toward HCHO oxidation.