Designing catalysts with suitable valence conduction band positions to generate reactive oxygen species (ROS) with moderate redox capacity is to achieve efficient photocatalytic biomass-selective value-added oxidation. This protocol addresses the issue by tuning material structural defects, altering the surface electronic structure, and ultimately enhancing the raw material’s performance. Here, an appropriate amount of one - dimensional nanorods α-MnO2 adjusted material structural defects, increased the adsorbed oxygen (Oads)/lattice oxygen (Olatt) and Mn3+ ratios, and served as an electron transport conduit, facilitating O₂ activation to generate ROS. The Cd1.7In2S4.7 solid solution enables the optimal valence band position by adjusting the Cd2+: In3+ ratio, thus selectively oxidizing 5-hydroxymethylfurfural (HMF) to 2,5-dicarbonylfuran (DFF). In situ XPS revealed that photogenerated electrons in Cd1.7In2S4.7 quickly transferred to the conduction band of α-MnO2, and photogenerated holes from α-MnO2 moved to the valence band of Cd1.7In2S4.7. This significantly enhanced the separation and transfer efficiency of photogenerated carriers at the interface. The optimal sample achieved 56% conversion of HMF and 72% selectivity of DFF under simulated sunlight. This protocol provides a new approach for the establishment of electron transport channel structures based on α-MnO2 constructs and value-added biomass photocatalytic conversion under simulated sunlight.

In this report, we successfully prepared nitrogen-doped porous carbon (N-PC)/manganese dioxide ( MnO2) composite for a high-performance supercapacitor. X-ray diffraction data revealed the α-MnO2 phase. Transmission electron microscopy confirmed that the nanostructured α-MnO2 nanoparticles were coated on the surface of N-PC. The N-PC/α-MnO2 composite delivered a capacitance of 525.7 F g− 1 at the charging current of 1.0 A g− 1. The higher capacitance of the composite could be owing to the synergy of MnO2 and N-PC. Besides, the electrode exhibited a 14.7% capacitance loss after 6000 charge– discharge cycles at 10 A g− 1 indicating good electrochemical stability.