Integrated Experimental-Theoretical Approach To Determine Reliable Molecular Reaction Mechanisms on Transition-Metal Oxide Surfaces

Engineering Energy Level of FeN4 Sites via Dual-Atom Site Construction Toward Efficient Oxygen Reduction

Single-atom catalysts based on metal-N₄ moieties and embedded in a graphite matrix (defined as MNC) are promising for oxygen reduction reaction (ORR). However, the performance of MNC catalysts is still far from satisfactory due to their imperfect adsorption energy to oxygen species. Herein, single-atom FeNC is leveraged as a model system and report an adjacent Ru-N₄ moiety modulation effect to optimize the catalyst's electronic configuration and ORR performance. Theoretical simulations and physical characterizations reveal that the incorporation of Ru-N₄ sites as the modulator can alter the d-band electronic energy of Fe center to weaken the FeO binding affinity, thus resulting in the lower adsorption energy of ORR intermediates at Fe sites. Thanks to the synergetic effects of neighboring Fe and Ru single-atom pairs, the FeN₄ /RuN₄ catalyst exhibits a half-wave potential of 0.958 V and negligible activity degradation after 10 000 cycles in 0.1 m KOH. Metal-air batteries using this catalyst in the cathode side exhibit a high power density of 219.5 mW cm^-2 and excellent cycling stability for over 2370 h, outperforming the state-of-the-art catalysts.

Multi-Bandgap Monolithic Metal Nanowire Percolation Network Sensor Integration by Reversible Selective Laser-Induced Redox

Active electronics are usually composed of semiconductor and metal electrodes which are connected by multiple vacuum deposition steps and photolithography patterning. However, the presence of interface of dissimilar material between semiconductor and metal electrode makes various problems in electrical contacts and mechanical failure. The ideal electronics should not have defective interfaces of dissimilar materials. In this study, we developed a novel method to fabricate active electronic components in a monolithic seamless fashion where both metal and semiconductor can be prepared from the same monolith material without creating a semiconductor-metal interface by reversible selective laser-induced redox (rSLIR) method. Furthermore, rSLIR can control the oxidation state of transition metal (Cu) to yield semiconductors with two different bandgap states (Cu₂O and CuO with bandgaps of 2.1 and 1.2 eV, respectively), which may allow multifunctional sensors with multiple bandgaps from the same materials. This novel method enables the seamless integration of single-phase Cu, Cu₂O, and CuO, simultaneously while allowing reversible, selective conversion between oxidation states by simply shining laser light. Moreover, we fabricated a flexible monolithic metal-semiconductor-metal multispectral photodetector that can detect multiple wavelengths. The unique monolithic characteristics of rSLIR process can provide next-generation electronics fabrication method overcoming the limitation of conventional photolithography methods.

Tuning selectivity in nickel oxide-catalyzed oxidative dehydrogenation of ethane through control over non-stoichiometric oxygen density

Thermally stable nickel oxide cubes are used to vary, exclusively, bulk non-stoichimetric oxygen density, and to rationalize ethene selectivities in the oxidative dehydorgenation of ethane under a wide range of conditions.

Pt1–O4 as active sites boosting CO oxidation via a non-classical Mars–van Krevelen mechanism

A new strategy to increase the total catalytic activity of SACs with low-loading noble metal for practical applications has been developed via fabricating super active SACs.