Defect Engineered Microcrystalline Cellulose for Enhanced Cocatalyst-Free Piezo-Catalytic H 2 Production.

Mechanical energy driven piezocatalytic hydrogen (H 2 ) production is a promising way to solve the energy crisis . But limited by the slow separation and transfer efficiency of piezoelectric charges generated on the surface of piezocatalysts , the piezocatalytic performance is still not satisfactory. Here, defect engineering is first used to optimize the piezocatalytic performance of microcrystalline cellulose (MCC). The piezocatalytic H 2 production rate of MCC with the optimal defect concentration can reach up to 84.47 µmol g -1 h -1 under ultrasonic vibration without any co-catalyst, which is ≈3.74 times higher than that of the pure MCC (22.65 µmol g -1 h -1 ). The enhanced H 2 production rate by piezoelectric catalysis is mainly due to the introduction of defect engineering on MCC, which disorders the symmetry of MCC crystal structure, improves the electrical conductivity of the material, and accelerates the separation and transfer efficiency of piezoelectric charges. Moreover, the piezocatalytic H 2 production rate of MCC with the optimal defect concentration can still reach up to 93.61 µmol g -1 h -1 in natural seawater, showingits commendable practicability. This study presents a novel view for designing marvelous-performance biomass piezocatalysts through defect engineering, which can efficiently convert mechanical energy into chemical energy .