Precise Lattice-Strain Modulation of Hematite Enabled by Gradient Doping of Mn for Enhanced Photoelectrocatalytic Oxidative CDC Bond Scission

The high-value utilization of biomass feedstock is fascinating but limited by efficient C & horbar;H activation to break C & horbar;C bonds. Herein, F-Fe2O3-Mn photoanodes with modulable compressive strain are fabricated by gradient infusion of Mn into F-doped hematite (F-Fe2O3), which is illustrated to be highly efficient for oxidative C & horbar;C bond cleavage of various bio-based 1,2-diols to produce benzoic acids or aromatic ketones (94.5-97.2% yields) in photoelectrocatalytic (PEC) device, coupling with a high H-2 production of 1180 mu mol cm(-2) (approximate to 96% yield). The gradient doping of Mn species into the photoelectrode bulk results in improved photoexcited carriers separation and transfer efficiency of the photoelectrode (3.41 mA cm(-2)). On the other hand, the lattice distortion induced by Mn doping also leads to a strain effect on F & horbar;Fe2O3 & horbar;Mn, which can precisely modulate the photoelectrode electronic structure. Control experiments, in situ characterization, and theoretical calculations elaborate that compressive strain is capable of adjusting the position of the d-band center to facilitate C & horbar;H activation, remarkably enabling PEC oxidative C & horbar;C bond breaking of 1,2-diol and the desorption of the oxidized product. This "one-stone-two-bird" strategy presents a straightforward protocol for efficiently breaking C & horbar;C bonds in organic and biomass transformations via PEC oxidation.