Active oxygen radicals (OH*/O*/OOH*) generated from oxygen evolution reaction (OER) play a crucial role in facilitating the electrooxidation of organic compounds into high value-added chemicals. However, constructing atomically precise active sites with a specific function to catalyze water-coupled electrooxidation reactions in a tandem system still confronts a great challenge. Herein, we propose a novel water-participating benzyl alcohol electrooxidation tandem process by constructing homogeneous isolated Fe–Pt dual-atom site catalysts on CoOOH nanosheet arrays (FePt DAC). The Fe and Pt dual atomic sites synergistically deliver excellent benzyl alcohol oxidation reaction activity with a high current density of 1500 mA·cm⁻² at a low potential of 1.49 V (vs. reversible hydrogen electrode (RHE)) and remarkable long-term durability without obvious attenuation after 530 h operation. In-situ Fourier-transform infrared spectroscopy, isotopic tracing experiment, and detailed theoretical calculations further reveal the tandem mechanism, in which the in-situ generated O* species on the Fe site through OER process serve as key intermediates that bridge the subsequent electrochemical benzyl alcohol oxidation on neighboring Pt site. This coupled oxidation mechanism turns competitive OER process into mutual benefits and provides insights to achieve directional transformation of chemical bonds via construction of collaborative dual atomic sites.

Photoelectrochemical (PEC) water splitting has great potential for solar energy conversion to hydrogen. However, the slow charge transfer in the photoanodes remains a core issue limiting the PEC performance. In this study, we address this issue by constructing a single-atom bridge (SAB) Cu-O₂N at the interface between BiVO₄ and covalent organic framework (COF) layer. X-ray absorption fine spectra and theoretical calculations demonstrate that the single-atom bridge is formed by the interfacial coordination reconstruction between BiVO₄ and COF layers and create intermediate electronic states to facilitate the hole extraction. As a result, the SAB photoanode exhibits enhanced PEC water oxidation performance. Specifically, it achieves a photocurrent density of 4.84 mA·cm⁻² at 1.23 V vs. reversible hydrogen electrode (RHE) in PEC simulant seawater splitting with a cocatalyst, higher than nearly all the previously reported BiVO₄-based photoanodes. This work offers valuable insights into fast charge transfer in PEC systems and proposes a promising strategy for designing efficient photoelectrodes for seawater splitting.

Immune therapy based on programmed death-ligand 1 (PD-L1) is widely used to treat human tumors. The current strategies to improve immune checkpoint blockade therapy fail in rescuing increased expression of PD-L1 in tumor issues. Here, we for the first time synthesized the metal–organic framework (MOF) nanocrystals of rare-earth element dysprosium (Dy) coordinated with tetrakis(4-carboxyphenyl) porphyrin (TCPP), which show well-defined two-dimensional morphologies. The MOF nanocrystals of Dy-TCPP could apparently reduce PD-L1 expression in tumor cells both in vitro and in vivo, and therefore display effective tumor treatment through immune therapy without any immune checkpoint inhibitor drugs. Considering the sensitivity of TCPP ligand toward ultrasound, the prepared Dy-TCPP can also realize sonodynamic therapy (SDT) besides immune therapy. In addition, the Dy-TCPP nanocrystals can efficiently obtain T₂-weight magnetic resonance imaging (MRI) of tumor sites. Our study provides the Dy-TCPP nanocrystals as promising diagnostic MRI-guided platforms for the combined treatment on tumors with SDT and immune therapy. Moreover, this strategy succeeds in reducing the elevated expression of PD-L1 in tumor cells, which might serve as a novel avenue for tumor immunotherapy in future.

Oxygen evolution reaction (OER) still suffers from the bottleneck in electrocatalytic water splitting. Herein, in virtue of volcano plots drawn by theoretical calculation, the (001) facet was screened as the superb facet of orthorhombic CoSe₂ for OER. Afterwards, CoSe₂(001) nanosheets were synthesized and the exposure ratio of (001) facet is controllable with thermodynamics methods effectively. The single-facet CoSe₂(001) delivered an overpotential as low as 240 mV at 10 mA·cm⁻² in 1 M KOH, which outperformed the bulk (380 mV) as well as other CoSe₂-base OER catalysts reported before. Especially, a shorter Co–Co path was observed in CoSe₂(001) by X­ray absorption spectroscopy. Further density functional theory (DFT) studies revealed that the reversible compression on the shorter Co–Co path could regulate the electronic structure of active sites during the OER process, and thus the energy barrier of the rate-determining step was reduced by 0.15 eV. This work could inspire more insights on the modification of electronic structure for OER electrocatalysts.