We presented a new type II heterojunction photocatalyst with a strong built-in electric field aligned between the spatially well-defined redox sites to effectively suppress the charge recombination for efficient photocatalytic hydrogen generation via HI splitting. This brings the hydrogen generation performance of the perovskite-based photocatalysts to a new horizon with a champion STH efficiency of 1.09% and a record hydrogen generation activity of 13.6 mmol g À1 h À1 under visible light.

Figure 3. Geometric and electronic structures of single/dual-atom, atomic clusters, and nanoparticles.

When it comes to using solar energy to promote catalytic reactions, photocatalysis technology is the first choice. However, sunlight can not only be directly converted into chemical energy through a photocatalytic process, it can also be converted through different energy-transfer pathways. Using sunlight as the energy source, photocatalytic reactions can proceed independently, and can also be coupled with other catalytic technologies to enhance the overall catalytic efficiency. Therefore, sunlight-driven catalytic reactions are diverse, and need to be given a specific definition. We propose a timely perspective for catalytic reactions driven by sunlight and give them a specific definition, namely "solar energy catalysis". The concept of different types of solar energy catalysis, such as photocatalysis, photothermal catalysis, solar cell powered electrocatalysis, and pyroelectric catalysis, are highlighted. Finally, their limitations and future research directions are discussed.

Complex oxide YVO multi-shell hollow spheres with uniform morphologies and controllable shell numbers are successfully prepared by using a newly developed and general composite yttrium-carbonaceous sphere templated approach. The prominent upconversion luminous intensity of the YVO :Yb /Er hollow spheres might be attributed to the enhanced near-infrared excitation light harvesting efficiency originated from the multiple reflections.

Although graphene oxide (GO) has shown enduring popularity in the research community, its synthesis remains cost prohibitive for many of its demonstrated applications. While significant progress has been made on developing an electrochemical route to GO, existing methods have key limitations regarding their cost and scalability. To overcome these challenges, we employ a combination of commercially available fused-deposition-modeling-based 3D printing and highly robust boron-doped diamond with a wide electrochemical potential window to fabricate a scalable packed-bed electrochemical reactor for GO production. The scalability of the reactor along the vertical and lateral dimensions was systematically demonstrated to facilitate its eventual industrial application. Our current reactor is cost-effective and capable of producing electrochemically derived GO (EGO) on a multiple-gram scale. By oxidizing flake graphite directly in an 11.6 M sulfuric acid electrolyte, the production of EGO was streamlined to a one-step electrochemical reaction, followed by a simple water-wash purification. Almost all of the converted graphite oxide can be recovered, and the final mass yield is typically 155% of the starting graphite material. The as-produced EGO is dispersible in water and other polar organic solvents (e.g., ethanol and dimethylformamide) and can be exfoliated down to predominantly single-layered GO. Through a detailed study of the product intermediates, the graphite was found to first form a stage III or higher graphite intercalation compound, followed by electrochemical oxidation proceeding from the top of the packed graphite bed down. The EGO can be easily deoxygenated with low-temperature thermal annealing (<200°C) to produce thermally converted EGO with significantly enhanced conductivity, and its promising application as a conductive nanofiller in lithium-ion battery cathodes was demonstrated. The simplicity, cost-effectiveness, and unique EGO properties make our current method a viable contender for large-scale synthesis of GO.