Polyoxometalate cluster-metal oxide hybrid subnanobelts on Hf-O-Mo interfacial electron coupling for piezocatalytic reduction of dilute CO2

Hybrid HfO 2 -PMA subnanobelts are synthesized by cluster–nuclei co-assembly. • Subnanometer belt morphology enhances piezoelectric polarization response. • Hf-O-Mo interfacial orbital coupling enhances charge separation. • PMA redox pairs act as electron buffers for efficient CO 2 activation. • Dilute CO 2 is efficiently converted into syngas via piezocatalysis. Efficient piezocatalytic conversion of dilute CO 2 into syngas offers a sustainable route for industrial flue gas valorization, yet conventional piezoelectric materials are often constrained by lattice rigidity and rapid charge recombination under weak mechanical stress. Herein, we constructed ultrathin 1D HfO 2 -phosphomolybdic acid (PMA) hybrid subnanobelts (SNBs) via cluster-nuclei co-assembly. The subnanometer architecture and flexible morphology induce an intense polarization response by leveraging the piezoelectric size effect, enabling HfO 2 -PMA SNBs to achieve remarkable CO and H 2 production rates of 4.5 and 5.8 mmol g −1 h −1 , respectively. In-situ FTIR spectra and density functional theory (DFT) calculations reveal that the asymmetric Hf-O-Mo interfacial coordination induces spontaneous electron transfer from HfO 2 to PMA, constructing a robust built-in electric field. Concurrently, the reversible redox properties of PMA clusters further enrich interfacial electron density and facilitate CO 2 adsorption and activation through Hf-O-Mo coupling, lowering the formation energy barrier of the key *COOH intermediates. This interfacial electronic structure engineering strategy establishes a novel paradigm for mechanical-energy-driven CO 2 conversion and offers a new approach for designing emerging sub-nanometer piezocatalysts. Download: Download high-res image (202KB) Download: Download full-size image