In2O3/Bi2O3 interface induces ultra-stable carbon dioxide electroreduction on heterogeneous InBiOx catalyst

The electrochemical reduction of CO2 (ERCO2) has emerged as one of the most promising methods for achieving both renewable energy storage and CO2 recovery. However, achieving both high selectivity and stability of catalysts remains a significant challenge. To address this challenge, this study investigated the selective synthesis of formate via ERCO2 at the interface of In2O3 and Bi2O3 in the InBiO6 composite material. Moreover, InBiO6 was synthesized using indium-based metal-organic frameworks as precursor, which underwent continuous processing through ion exchange and thermal reduction. The results revealed that the formate Faradaic efficiency (FEformate) of InBiO6 reached nearly 100 % at -0.86 V vs. reversible hydrogen electrode (RHE) and remained above 90 % after continuous 317-h electrolysis, which exceeded those of previously reported indium-based catalysts. Additionally, the InBiO6 composite material exhibited an FEformate exceeding 80 % across a wide potential range of 500 mV from -0.76 to -1.26 V vs. RHE. Density-functional theory analysis confirmed that the heterogeneous interface of InBiO6 played a role in achieving optimal free energies for *OCHO on its surface. Furthermore, the addition of Bi to the InBiO6 matrix facilitated electron transfer and altered the electronic structure of In2O3, thereby enhancing the adsorption, decomposition, and formate production of *OCHO.

2D MOF Structure Tuning Atomic Ru Sites for Efficient and Robust Proton Exchange Membrane Water Electrolysis

Developing cost-effective ruthenium (Ru)-based HER electrocatalysts as alternatives to commercial Pt/C is crucial for the advancement of proton exchange membrane water electrolysis (PEMWE). However, the strong hydrogen adsorption of Ru-based catalysts restricts its activity. Herein, a strategy is reported to tune the electronic structure and improve mass transfer by implanting Ru atoms onto the (002) facet of two-dimensional zeolitic imidazolate framework-67 (Ru@LZIF(002)) to optimize the d-band center (εd) of Ru and the hydrogen spillover behavior. Benefiting from the ultrathin nanosheet structure and optimized εd of Ru, the over-strong H adsorption energy is weakened and the electron/mass transfer is facilitated. Ru@LZIF(002) exhibits an overpotential of 9.2 mV at 10 mA cm-2 and a long-lasting stability of 35 days at 100 mA cm-2. The mass activity and price activity of Ru@LZIF(002) is 2.9 and 14.7 times higher than Pt/C, respectively. More impressively, Ru@LZIF(002) delivers a cell voltage of 2.01 V at a high current density of 4 A cm-2 in PEMWE. The excellent long-term durability of 1200 hours operating at 4 A cm-2 with an ultralow decay rate of 7.5 × 10-3 mV h-1 has been achieved, making it promising as a cost-effective alternative to Pt/C catalyst for PEMWE applications.

Cu-Mo Bimetal Modulated Multifunctional Carbon Nanofibers Promoting the Polysulfides Conversion for High-Sulfur-Loading Lithium-Sulfur Batteries

High sulfur loading is essential for achieving high energy density lithium-sulfur (Li-S) batteries. However, serious issues such as low sulfur utilization, poor cycling stability, and sluggish rate performance have been exposed when increasing the sulfur loading for freestanding cathodes. To solve these problems, the adsorption/catalytic ability of high-sulfur-loading cathode toward polysulfides must be improved. Herein, based on excellent properties of cationic MOFs, we proposed that Cu-Mo bimetallic nanoparticles embedded in multifunctional freestanding nitrogen-doped porous carbon nanofibers (Cu-Mo@NPCN) with efficient catalytic sites could be prepared by facile MoO₄^2- anion exchange of cationic MOFs. And, the sulfur embedded in Cu-Mo@NPCN was directly used as self-supporting electrodes, enabling a high areal capacity, good rate performance, and decent cycling stability even under high sulfur loading. The freestanding Cu-Mo@NPCN/10.3S cathode achieves a high volumetric capacity of 1163 mA h cm^-3 and a decent areal capacity of 9.3 mA h cm^-2 at 0.2 C with a sulfur loading of 10.3 mg cm^-2. This work provides an innovative approach for engineering a freestanding sulfur cathode and would forward the development of cationic MOF-derived bimetallic catalysts in various energy storage systems.

Remarkably enhanced ion-exchange capacity of H2O2-intercalated layered titanate

H2O2-intercalated layered titanate H1.07Ti1.73O4 (H2O2-HTO) exhibits a dramatically enhanced ion-exchange capacity and remarkably improved reaction rate with various divalent cations. The intercalation can increase the negative charge density of the TiO6 octahedral layer and the number of ion-exchangeable H+ by forming a Ti(iv)-O-O-H bond that is the driving force to change the ion exchange performance.