While acidic oxygen evolution reaction plays a critical role in electrochemical energy conversion devices, the sluggish reaction kinetics and poor stability in acidic electrolyte challenges materials development. Unlike traditional nano-structuring approaches, this work focuses on the structural symmetry breaking to rearrange spin electron occupation and optimize spin-dependent orbital interaction to alter charge transfer between catalysts and reactants. Herein, we propose an atomic half-disordering strategy in multistage-hybridized BixEr2-xRu2O7 pyrochlores to reconfigure orbital degeneracy and spin-related electron occupation. This strategy involves controlling the bonding interaction of Bi-6s lone pair electrons, in which partial atom rearrangement makes the active sites transform into asymmetric high-spin states from symmetric low-spin states. As a result, the half-disordered BixEr2-xRu2O7 pyrochlores demonstrate an overpotential of ~0.18 V at 10 mA cm−2 accompanied with excellent stability of 100 h in acidic electrolyte. Our findings not only provide a strategy for designing atom-disorder-related catalysts, but also provides a deeper understanding of the spin-related acidic oxygen evolution reaction kinetics.

Growing interest has been shown in photocatalytic hydrogen evolution (PHE) based on graphitic carbon nitride (g-C 3 N 4 , CN). The design of high-efficiency CN-based photocatalysts is a key to achieving high PHE performance. Herein, we offer a review to encapsulate the current approach in the thoughtful design of donor−acceptor type CN (DA-CN), which is an excellent tactic to optimize the photocatalytic properties of primal CN. Concretely, it starts with an introduction emphasizing the basic properties and limitations of primal CN as well as the superiority of DA-CN photocatalysts. Following that, the creation of DA-CN photocatalysts and the mechanism behind improved PHE performance are highlighted from three aspects, namely, interfacial heterojunction, molecular doping, and intramolecular D−A structure. Lastly, based on the previous work, a thorough overview on the primary difficulties and chances this hot area and the implications for future research are presented. Overall, it is envisioned that this review will provide a new perspective for revealing the application of DA-CN photocatalysts in PHE and adds invaluable knowledge for the development of more effective photocatalysts.

Simultaneously realizing efficient intramolecular charge transfer and mass transport in metal-free polymer photocatalysts is critical but challenging for environmental remediation. Herein, we develop a simple strategy to construct holey polymeric carbon nitride (PCN)-based donor−π−acceptor organic conjugated polymers via copolymerizing urea with 5bromo-2-thiophenecarboxaldehyde (PCN−5B2T D−π−A OCPs). The resultant PCN−5B2T D−π−A OCPs extended the πconjugate structure and introduced abundant micro-, meso-, and macro-pores, which greatly promoted intramolecular charge transfer, light absorption, and mass transport and thus significantly enhanced the photocatalytic performance in pollutant degradation. The apparent rate constant of the optimized PCN−5B2T D−π−A OCP for 2-mercaptobenzothiazole (2-MBT) removal is ∼10 times higher than that of the pure PCN. Density functional theory calculations reveal that the photogenerated electrons in PCN−5B2T D−π−A OCPs are much easier to transfer from the donor tertiary amine group to the benzene π-bridge and then to the acceptor imine group, while 2-MBT is more easily adsorbed on πbridge and reacts with the photogenerated holes. A Fukui function calculation on the intermediates of 2-MBT predicted the realtime changing of actual reaction sites during the entire degradation process. Additionally, computational fluid dynamics further verified the rapid mass transport in holey PCN−5B2T D−π−A OCPs. These results demonstrate a novel concept toward highly efficient photocatalysis for environmental remediation by improving both intramolecular charge transfer and mass transport.

The mediating role of surface structure of In 2 O 3 on the adsorption and photocatalytic degradation of perfluorooctanoic acid (PFOA) is important but still unclear. Herein, In 2 O 3 with various oxygen vacancy concentrations are designed by pyrolyzing a metal organic framework (MIL-68(In)-NH 2 ) for PFOA degradation. The results demonstrate that the In 2 O 3 -400 obtained at a lower pyrolysis temperature of 400 °C possesses the highest oxygen vacancy concentration, thus exhibiting remarkably boosted adsorption capacity and degradation performance for PFOA. Adsorption kinetics, isotherm adsorption model, and Fourier transform infrared spectroscopy (FTIR) results show that PFOA is chemically adsorbed on the In 2 O 3 -400 surface in the form of monodentate mode. Notably, there is a linear correlation between the adsorption capacity and the degradation kinetic rate constant of In 2 O 3 -400 for PFOA, indicating that surface adsorption is a prerequisite for the PFOA degradation. Furthermore, density functional theory (DFT) results indicate that oxygen vacancies, as the structural characteristic for PFOA chemisorption, can promote the nonradical oxidation process of PFOA. This study provides a new perspective to explain the role of the surface structure of In 2 O 3 in relation to its adsorption and photocatalytic performance for PFOA, which is helpful for the development of more effective PFOA adsorption coupled degradation technology.

Simultaneously improving electron and mass transfer processes is full of challenges for electrode material design. To this end, three-dimensional (3D) porous electrode materials were obtained via covalent combination between defective 1T-MoS 2 nanosheets and polyaniline (PANI) through hydrothermal/ solvothermal processes and surface polymerization reactions. Our experimental results and density functional theory calculations jointly reveal that PANI molecules can not only intercalate into van der Waals (vdW) gaps of 1T-MoS 2 nanosheets but also chemically adsorb onto S-vacancy clusters (via Mo−N covalent bonds), rather than single atomic S-vacancies due to steric effects. Similarly, the geometric structure of PANI in the vdW gaps of 1T-MoS 2 nanosheets possesses a flat-lying configuration for better stability. Compared to surface functionalization, interlayer intercalation has more profound effects on electronic structures for improving electrochemical properties, including reduced band gaps, small effective electron masses, and high mobility. As a proof-of-concept application, the 1T-MoS 2 −PANI nanocomposites were used to construct an electrochemical sensor for trace Cu 2+ , which exhibits high sensitivity and selectivity with a wide linear range from 3 to 450 nM and a low detection limit because of excellent conductivity, a low contact barrier against electron transfer, high mass transfer, and strong coordination interactions between PANI and Cu 2+ .