RESUMO
Preparation of high-performance and durable electrocatalysts for anion exchange membrane water electrolysis is a crucial step toward the broad implementation of this technology. Here, we present an easily tunable, one-step hydrothermal method for the preparation of Ni-based (NiX, X = Co, Fe) layered double hydroxide nanoparticles (LDHNPs) for the oxygen evolution reaction (OER), using tris(hydroxymethyl)aminomethane (Tris-NH2) for particle growth control. The LDHNPs are used as building blocks of mesoporous mixed metal oxides (MMOs) with a block copolymer template (Pluronic F127), followed by thermal treatment at 250 °C. NiX MMOs have a significantly larger surface area compared to the analogous LDHNPs. NiX LDHNPs and MMOs exhibit excellent performance and long-term cycling stability, making them promising OER catalysts. Moreover, this versatile method can be easily tailored and scaled up for the preparation of platinum group metal-free electrocatalysts for other reactions of interest, which highlights the relevance of this work to the field of electrocatalysis.
RESUMO
Advancements in hypothetical metal-organic framework (hMOF) databases and construction tools have resulted in a rapidly expanding chemical design space for nanoporous materials. The bulk of these hypothetical structures are constructed using structural building units (SBUs) derived from experimental MOF structures, often collected from the CoRE-MOF database. Recent investigations into the state of these deposited experimental structures' chemical accuracy identified an array of common structural errors, including omitted protons, missing counterions, and disordered structures. These structural errors propagate into the SBUs mined from experimental MOFs, culminating in inaccurate hMOF structures possessing net charges or missing atoms which were not accounted for previously. This work demonstrates how manual investigation was applied to diagnose structural errors in SBUs obtained from several popular hMOF construction tools and databases. An analysis of the prevailing errors discovered during the examination process is provided along with representative cases to aid with error detection in future studies involving SBU extraction and hMOF construction. A novel repair protocol was established and employed to generate a library of SBUs that are hand-examined and labeled with enhanced detail (HEALED). This repaired library of SBUs contains 952 inorganic SBUs and 568 organic SBUs ideally suited for the generation of hypothetical frameworks that are chemically accurate and properly charge labeled. Additionally, case studies following the effects of SBU errors on electrostatic potential-fitted charges and GCMC-simulated gas adsorption predictions are presented to highlight the significance of using chemically accurate hMOF structures exclusively in all screening efforts going forward.
