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1. Microenvironmental Engineering of Active Sites for Selective Catalytic Hydrolysis of Acetals

   https://doi.org/10.1039/D5OB00629E  

   Sharma, Mansi; Zhao, Yan (January 2025, Organic & Biomolecular Chemistry)

   Rational design of synthetic catalysts that mimic enzymes in catalysis and substrate selectivity is a long-standing goal of chemists. We report bottom-up synthesis of artificial acetal hydrolase that hydrolyzes its substrate with high selectivity under otherwise impossible neutral and basic conditions. Our synthetic method allows facile modification of the active site, including introduction of a local water pool near the acetal group of the bound substrate to alter the catalytic mechanism, or installment of a secondary catalytic group to enhance the catalytic activity. 

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2. Advances in the synthesis, characterisation, and mechanistic understanding of active sites in Fe-zeolites for redox catalysts

   https://doi.org/10.1039/D0DT01857K  

   Bols, Max L.; Rhoda, Hannah M.; Snyder, Benjamin E.; Solomon, Edward I.; Pierloot, Kristine; Schoonheydt, Robert A.; Sels, Bert F. (November 2020, Dalton Transactions)

   null (Ed.)

   The recent research developments on the active sites in Fe-zeolites for redox catalysis are discussed. Building on the characterisation of the α-Fe/α-O active sites in the beta and chabazite zeolites, we demonstrate a bottom-up approach to successfully understand and develop Fe-zeolite catalysts. We use the room temperature benzene to phenol reaction as a relevant example. We then suggest how the spectroscopic identification of other monomeric and dimeric iron sites could be tackled. The challenges in the characterisation of active sites and intermediates in NO X selective catalytic reduction catalysts and further development of catalysts for mild partial methane oxidation are briefly discussed. 

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3. Strategies for Designing the Catalytic Environment Beyond the Active site of Heterogeneous Supported Metal Catalysts

   https://doi.org/10.1007/s11244-023-01835-2  

   Bhat, Samiha; Pagán-Torres, Yomaira J.; Nikolla, Eranda (June 2023, Topics in Catalysis)

   Significant emphasis has been placed recently in engineering the catalytic environment beyond the active site for tuning the activity, selectivity, and stability of supported metal catalysts for targeted reactions. The environment around the active site in supported catalysts can be modified by introducing multi-dimensionality through alloying, encapsulation, and surface bound ligands. In this Review, we provide a summary of synthesis strategies that have enabled the design of multifunctionality and multidimensionality in heterogeneous supported catalysts. We specifically discuss alloys, encapsulated/inverted catalytic structures, and ligand capped metal nanoparticle systems. We highlight the effects on catalyst activity, selectivity and stability that arise from modifying the neighboring two-dimensional environment through alloying or three-dimensional environment through encapsulation with porous inorganic films or surface organic moieties. We conclude by providing a short perspective on the promises and remaining challenges associated with engineering the local environment around the active sites of supported heterogeneous catalysts. 

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4. Two-dimensional transition metal carbides as supports for tuning the chemistry of catalytic nanoparticles

   https://doi.org/10.1038/s41467-018-07502-5  

   Li, Zhe; Yu, Liang; Milligan, Cory; Ma, Tao; Zhou, Lin; Cui, Yanran; Qi, Zhiyuan; Libretto, Nicole; Xu, Biao; Luo, Junwei; et al (December 2018, Nature Communications)

   Abstract Supported nanoparticles are broadly employed in industrial catalytic processes, where the active sites can be tuned by metal-support interactions (MSIs). Although it is well accepted that supports can modify the chemistry of metal nanoparticles, systematic utilization of MSIs for achieving desired catalytic performance is still challenging. The developments of supports with appropriate chemical properties and identification of the resulting active sites are the main barriers. Here, we develop two-dimensional transition metal carbides (MXenes) supported platinum as efficient catalysts for light alkane dehydrogenations. Ordered Pt 3 Ti and surface Pt 3 Nb intermetallic compound nanoparticles are formed via reactive metal-support interactions on Pt/Ti 3 C 2 T x and Pt/Nb 2 CT x catalysts, respectively. MXene supports modulate the nature of the active sites, making them highly selective toward C–H activation. Such exploitation of the MSIs makes MXenes promising platforms with versatile chemical reactivity and tunability for facile design of supported intermetallic nanoparticles over a wide range of compositions and structures. 

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5. Atomically dispersed Fe–N–C decorated with Pt-alloy core–shell nanoparticles for improved activity and durability towards oxygen reduction

   https://doi.org/10.1039/d0ee00832j  

   Ao, Xiang; Zhang, Wei; Zhao, Bote; Ding, Yong; Nam, Gyutae; Soule, Luke; Abdelhafiz, Ali; Wang, Chundong; Liu, Meilin (September 2020, Energy & Environmental Science)

   null (Ed.)

   One of the key challenges that hinders broad commercialization of proton exchange membrane fuel cells is the high cost and inadequate performance of the catalysts for the oxygen reduction reaction (ORR). Here we report a composite ORR catalyst consisting of ordered intermetallic Pt-alloy nanoparticles attached to an N-doped carbon substrate with atomically dispersed Fe–N–C sites, demonstrating substantially enhanced catalytic activity and durability, achieving a half-wave potential of 0.923 V ( vs.  RHE) and negligible activity loss after 5000 cycles of an accelerated durability test. The composite catalyst is prepared by deposition of Pt nanoparticles on an N-doped carbon substrate with atomically dispersed Fe–N–C sites derived from a metal–organic framework and subsequent thermal treatment. The latter results in the formation of core–shell structured Pt-alloy nanoparticles with ordered intermetallic Pt 3 M (M = Fe and Zn) as the core and Pt atoms on the shell surface, which is beneficial to both the ORR activity and stability. The presence of Fe in the porous Fe–N–C substrate not only provides more active sites for the ORR but also effectively enhances the durability of the composite catalyst. The observed enhancement in performance is attributed mainly to the unique structure of the composite catalyst, as confirmed by experimental measurements and computational analyses. Furthermore, a fuel cell constructed using the as-developed ORR catalyst demonstrates a peak power density of 1.31 W cm −2 . The strategy developed in this work is applicable to the development of composite catalysts for other electrocatalytic reactions. 

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