Climate change has driven the development of sustainable catalytic processes to power our society. Applying solar energy to drive catalytic reactions is regarded as a green chemistry for value-added conversions. The photogenerated electrons have been applied for many promising processes such as hydrogen production, carbon dioxide reduction and nitrogen fixation, but the photogenerated holes are less focused on. Other than the traditional oxygen evolution reaction (OER), which has low economic value, some more promising reactions are expected to be explored, including water oxidation for hydrogen peroxide generation and methane oxidation for methanol generation. In this review, we will summarize the alternative partial water oxidation reaction (PWOR) and partial methane oxidation reaction (PMOR) for the production of useful hydrogen peroxide and methanol, respectively. Advanced materials engineering has been implemented to perform valuable conversions of photogenerated holes. The design concepts, principles, and traditional catalysts for PWOR and PMOR have been summarized. It is expected that this review will advance solar-driven reactions to another innovative stage with the aim of creating more value from photogenerated charges.
Micro-sized silicon (μSi) is a promising anode for next-generation high-energy-density lithium-ion batteries (LIBs) due to its high capacity and excellent tap density. However, its severe volume fluctuations induce mechanical degradation and rapid capacity fading. Here, we develop a strain-adaptive design to construct hierarchical Si/graphene composite microspheres (DSMG@C) via scalable spray-drying and chemical vapor deposition (CVD). The architecture integrates an internal graphene scaffold, dual-scale (micro/nano) silicon, and a conformal ∼10 nm graphitic carbon shell, enabling an internal compliant framework with distributed microvoids coupled with an external conformal carbon confinement layer. The graphene-based framework and distributed microvoids accommodate local deformation, while nano-Si serves as an adaptive interstitial filler to densify contacts and disperse stress. The nano-Si disperses stress and fills voids to enhance densification, while the carbon shell reinforces mechanical stability and interfacial robustness. As a result, the DSMG@C anode delivers a high reversible capacity of 1062.8 mAh g-1 after 500 cycles at 1 A g-1, an initial coulombic efficiency of 90.8%, and a superior volumetric capacity owing to its 1.22 g cm-3 compacted density. Kinetic and mechanical analyses confirm its fast ion/electron transport and durable structural integrity. Full cells paired with LiFePO4 exhibit a discharge capacity of 123.4 mAh g-1 at 1 C after 200 cycles with an initial coulombic efficiency (ICE) of 92.7%, demonstrating strong practical potential. This work offers an effective strategy for designing high-performance Si-based anodes through multiscale structural engineering.
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