Activated Single-Phase Ti4 O7 Nanosheets with Efficient Use of Precious Metal for Inspired Oxygen Reduction Reaction.

Invited for the cover of this issue is the group of Yu Wang, Feipeng Wang, and co-workers at Chongqing University. The image depicts how activated single-crystal Ti4 O7 nanosheets loaded with precious metals can be used as highly efficient and stable materials to make fuel-cell electrodes for intermittent renewable energy storage in power grids. Read the full text of the article at 10.1002/chem.202202580.

Activated Single-Phase Ti4 O7 Nanosheets with Efficient Use of Precious Metal for Inspired Oxygen Reduction Reaction.

The oxygen reduction reaction (ORR) is central to modern energy storage and conversion technologies for grids such as fuel cells and electrolyzers, but challenges remain due to the lack of reliable, economic, and durable electrocatalysts. Here, we develop single-crystal conductive black titanium (Ti4 O7 ) nanosheets (NSs) as a new precious metal carrier based on sacrificial hard templates and ultrasonic-assisted peeling, and deposit Pt clusters on Ti4 O7 NSs induced by wetness impregnation under the irradiation of visible light (VI; 650 nm). Pt/Ti4 O7 NSs provide Ti3+ , Pt2+ , and Pt0+ continuous active sites for the ORR multielectron process, achieving synergy among them. The assistance of visible light not only makes a more uniform and smaller distribution of Pt nanoclusters, but also strengthens the charge transfer, thereby constructing a strong metal-support interaction interface. VI-Pt/Ti4 O7 NSs show superior initial oxidation potential and a mass activity of 1.61 A mg-1 Pt at a E1/2 =0.91 V, which is nine times higher than that of commercial Pt/C. This work provides an effective strategy for achieving high-value applications of titanium sub-oxides and further explores the enhanced interface in metals Tin O2n-1 by light radiation.

NP monolayer supported transition-metal single atoms for electrochemical water splitting: a theoretical study.

The development of cost-effective and highly efficient electrocatalysts for water splitting is highly desirable but remains an ongoing challenge. Numerous single-atom catalysts (SACs) have achieved satisfactory performances in this area; however, non-carbon metal-free substrates have been rarely explored. Herein, we report a series of single-metal atoms supported on a novel two-dimensional NP monolayer as promising electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) by theoretical calculations. Our results disclose that Ti@NP, V@NP and Ir@NP exhibit desirable catalytic activity for the HER with extremely low of -0.004, -0.051, and 0.017 eV, respectively. More importantly, the calculated activation barriers for the Tafel reactions of these SACs are much lower than those for the benchmark Pt catalysts. In addition, Pt@NP shows the lowest ηOER of 0.495 V, followed by Rh@NP (ηOER = 0.548 V), which are even superior to that of state-of-the-art IrO2. This work highlights the potential application of metal-free supports in SACs, which also further enriches the application of a NP monolayer in other related electrochemical processes.

Au(111)@Ti6O11 heterostructure composites with enhanced synergistic effects as efficient electrocatalysts for the hydrogen evolution reaction.

Developing cost-effective electrocatalysts for the hydrogen evolution reaction (HER) is of great significance for the renewable energy field. The Magnéli phase TinO2n-1 (4 ≤ n ≤ 10) has attracted much attention as a promising carbon-free support for electrocatalysts due to its high electrical conductivity and favorable electrochemical stability. Herein, we report the synthesis of a specific crystal-plane coupling heterostructure between Au(111) nanoparticles (NPs) and Ti6O11 by photoreduction. Benefitting from the modification of the electronic structure and synergistic effects of the heterostructure, the electron density around Au atoms is enhanced, and the Gibbs free energy of hydrogen absorption (ΔGH*) was dramatically optimized to facilitate the HER process. The best electrocatalyst Au(111)@Ti6O11-50 exhibits a lower overpotential of 49 mV at a current density of -10 mA cm-2 and a Tafel slope of 39 mV dec-1 in 0.5 M H2SO4, and shows long-term electrochemical stability over 30 h. Au(111)@Ti6O11-50 shows a mass activity of 9.25 A mgAu-1, which is about 18 times higher than that of commercial Pt/C (0.51 A mgPt-1). Meanwhile, the density functional theory (DFT) calculations suggest that the ΔGH* of Au(111)@Ti6O11 is -0.098 eV, which is comparable to that of Pt (-0.09 eV). This work would be a powerful guide for the realization of efficient utilization of noble metals in catalysis.