Significance: Photocatalysts frequently require simultaneous loading of oxidative and reductive cocatalysts to achieve both efficient half-reactions within a single material. Nevertheless, unregulated loading and distribution of two cocatalysts will result in direct contact between oxidation and reduction centers, leading to detrimental charge recombination. This research presents a center/edge approach to load two redox cocatalysts with controlled physical separation in atomistic scale using single-atom architecture. This spatial separation is critical for enhancing surface charge separation and achieving efficient H ₂ O ₂ production. We report that redox cocatalysts are spatially separated on a two-dimensional (2D) photocatalyst, which opens an approach for achieving both efficient oxidation and reduction reactions on 2D photocatalysts.

Isothermal Water Splitting: Solar concentrators can create extremely high temperatures that can drive chemical reactions, including the thermal splitting of water to provide hydrogen. A metal oxide catalyst is needed that is usually cycled between hotter conditions where it is reduced and cooler conditions where it is reoxidized by water. This cycling can limit catalyst lifetime, which can be costly. Muhich et al. (p. 540 ; see the Perspective by Roeb and Sattler ) developed an approach that allowed the redox cycle to be driven isothermally, using pressure swings.

Single atom catalysts have been found to exhibit superior selectivity over nanoparticulate catalysts for catalytic reactions such as hydrogenation due to their single-site nature. However, improved selectively is often accompanied by loss of activity and slow kinetics. Here we demonstrate that neighboring Pd single atom catalysts retain the high selectivity merit of sparsely isolated single atom catalysts, while the cooperative interactions between neighboring atoms greatly enhance the activity for hydrogenation of carbon-halogen bonds. Experimental results and computational calculations suggest that neighboring Pd atoms work in synergy to lower the energy of key meta-stable reactions steps, i.e., initial water desorption and final hydrogenated product desorption. The placement of neighboring Pd atoms also contribute to nearly exclusive hydrogenation of carbon-chlorine bond without altering any other bonds in organohalogens. The promising hydrogenation performance achieved by neighboring single atoms sheds light on a new approach for manipulating the activity and selectivity of single atom catalysts that are increasingly studied in multiple applications.

Despite the fundamental role oxygen vacancy formation energies play in a broad range of important energy applications, their relationships with the intrinsic bulk properties of solid oxides remain elusive. Our study of oxygen vacancy formation in La_1−xSr_xBO₃ perovskites (BCr, Mn, Fe, Co, and Ni) conducted using modern, electronic structure theory and solid-state defect models demonstrates that a combination of two fundamental and intrinsic materials properties, the oxide enthalpy of formation and the minimum band gap energy, accurately correlate with oxygen vacancy formation energies. The energy to form a single, neutral oxygen vacancy decreases with both the oxide enthalpy of formation and the band gap energy in agreement with the relation of the former to metal–oxygen bond strengths and of the latter to the energy of the oxygen vacancy electron density redistribution. These findings extend our understanding of the nature of oxygen vacancy formation in complex oxides and provide a fundamental method for predicting oxygen vacancy formation energies using purely intrinsic bulk properties.