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Metal hydrides are crucial intermediates in numerous catalytic reactions. Intensive efforts have been dedicated to constructing molecular metal hydrides, where toxic precursors and delicate mediators are usually involved. Herein, we demonstrate a facile pressure-induced methodology to generate a cost-effective heterogeneous electrocatalytic metal hydride surface for sustainable hydrogen transfer. Taking carbon dioxide (CO 2 ) electroreduction as a model system and zinc (Zn), a well-known carbon monoxide (CO)-selective catalyst, as a model catalyst, we showcase a homogeneous-type hydrogen atom transfer process induced by heterogeneous hydride surfaces, enabling direct hydrogenation pathways traditionally considered "prohibited". Specifically, the maximal Faradaic efficiency for formate is enhanced by ~fivefold to 83% under ambient conditions. Experimental and theoretical analyses reveal that unlike the distal hydrogenation route for CO 2 to CO over pristine Zn, the Zn hydride surface enables direct hydrogenation at the carbon site of CO 2 to form formate. This work provides a promising material platform for sustainable synthesis., (© 2024. The Author(s).)

The directional transformation of carbon dioxide (CO 2 ) with renewable hydrogen into specific carbon-heavy products (C 6+ ) of high value presents a sustainable route for net-zero chemical manufacture. However, it is still challenging to simultaneously achieve high activity and selectivity due to the unbalanced CO 2 hydrogenation and C-C coupling rates on complementary active sites in a bifunctional catalyst, thus causing unexpected secondary reaction. Here we report LaFeO 3 perovskite-mediated directional tandem conversion of CO 2 towards heavy aromatics with high CO 2 conversion (> 60%), exceptional aromatics selectivity among hydrocarbons (> 85%), and no obvious deactivation for 1000 hours. This is enabled by disentangling the CO 2 hydrogenation domain from the C-C coupling domain in the tandem system for Iron-based catalyst. Unlike other active Fe oxides showing wide hydrocarbon product distribution due to carbide formation, LaFeO 3 by design is endowed with superior resistance to carburization, therefore inhibiting uncontrolled C-C coupling on oxide and isolating aromatics formation in the zeolite. In-situ spectroscopic evidence and theoretical calculations reveal an oxygenate-rich surface chemistry of LaFeO 3 , that easily escape from the oxide surface for further precise C-C coupling inside zeolites, thus steering CO 2 -HCOOH/H 2 CO-Aromatics reaction pathway to enable a high yield of aromatics., (© 2024. The Author(s).)

The removal of acetylene impurities remains important yet challenging to the ethylene downstream industry. Current thermocatalytic semihydrogenation processes require high temperature and excess hydrogen to guarantee complete acetylene conversion. For this reason, renewable electricity-based electrocatalytic semihydrogenation of acetylene over Cu-based catalysts is an attractive route compared to the energy-intensive thermocatalytic processes. However, active Cu electrocatalysts still face competition from side reactions and often require high overpotentials. Here, we present an undercoordinated Cu nanodots catalyst with an onset potential of -0.15 V versus reversible hydrogen electrode that can exclusively convert C 2 H 2 to C 2 H 4 with a maximum Faradaic efficiency of ~95.9% and high intrinsic activity in excess of -450 mA cm -2 under pure C 2 H 2 flow. Subsequently, we successfully demonstrate simulated crude ethylene purification, continuously producing polymer-grade C 2 H 4 with <1 ppm C 2 H 2 for 130 h at a space velocity of 1.35 × 10 5  ml g cat -1 h -1 . Theoretical calculations and in situ spectroscopies reveal a lower energy barrier for acetylene semihydrogenation over undercoordinated Cu sites than nondefective Cu surface, resulting in the excellent C 2 H 2 -to-C 2 H 4 catalytic activity of Cu nanodots., (© 2023. The Author(s).)

Heteroatom-doping is a practical means to boost RuO 2 for acidic oxygen evolution reaction (OER). However, a major drawback is conventional dopants have static electron redistribution. Here, we report that Re dopants in Re 0.06 Ru 0.94 O 2 undergo a dynamic electron accepting-donating that adaptively boosts activity and stability, which is different from conventional dopants with static dopant electron redistribution. We show Re dopants during OER, (1) accept electrons at the on-site potential to activate Ru site, and (2) donate electrons back at large overpotential and prevent Ru dissolution. We confirm via in situ characterizations and first-principle computation that the dynamic electron-interaction between Re and Ru facilitates the adsorbate evolution mechanism and lowers adsorption energies for oxygen intermediates to boost activity and stability of Re 0.06 Ru 0.94 O 2 . We demonstrate a high mass activity of 500 A g cata. -1 (7811 A g Re-Ru -1 ) and a high stability number of S-number = 4.0 × 10 6  n oxygen  n Ru -1 to outperform most electrocatalysts. We conclude that dynamic dopants can be used to boost activity and stability of active sites and therefore guide the design of adaptive electrocatalysts for clean energy conversions., (© 2023. The Author(s).)

Spontaneous monodispersion of reducible active species (e.g., Fe, Co) and their stabilization in reductive atmospheres remain a key challenge in catalytic syngas chemistry. In this study, we present a series of catalysts including spontaneously monodispersed and enriched Fe on ZnCr 2 O 4 . Deep investigation shows remarkable performance in the syngas-to-aromatic reaction only when monodispersed Fe coupled with a H-ZSM-5 zeolite. Monodispersed Fe increases the turnover frequency from 0.14 to 0.48 s -1 without sacrificing the record high selectivity of total aromatics (80-90%) at a single pass. The increased activity is ascribed to more efficient activation of CO and H 2 at oxygen vacancy nearest to the isolated Fe site and the prevention of carbide formation. Atomic precise characterization and theoretical calculations shed light on the origin and implications of spontaneous Fe monodispersion, which provide guidance to the design of next-generation catalyst for upgrading small molecules to synthetic fuels and chemicals., (© 2022. The Author(s).)

The electrochemical conversion of carbon di-/monoxide into commodity chemicals paves a way towards a sustainable society but it also presents one of the great challenges in catalysis. Herein, we present the trends in selectivity towards specific dicarbon oxygenate/hydrocarbon products from carbon monoxide reduction on transition metal catalysts, with special focus on copper. We unveil the distinctive role of electrolyte pH in tuning the dicarbon oxygenate/hydrocarbon selectivity. The understanding is based on density functional theory calculated energetics and microkinetic modeling. We identify the critical reaction steps determining selectivity and relate their transition state energies to two simple descriptors, the carbon and hydroxide binding strengths. The atomistic insight gained enables us to rationalize a number of experimental observations and provides avenues towards the design of selective electrocatalysts for liquid fuel production from carbon di-/monoxide., (© 2022. The Author(s).)

Preventing the stacking of graphene is essential to exploiting its full potential in energy-storage applications. The introduction of spacers into graphene layers always results in a change in the intrinsic properties of graphene and/or induces complexity at the interfaces. Here we show the synthesis of an intrinsically unstacked double-layer templated graphene via template-directed chemical vapour deposition. The as-obtained graphene is composed of two unstacked graphene layers separated by a large amount of mesosized protuberances and can be used for high-power lithium-sulphur batteries with excellent high-rate performance. Even after 1,000 cycles, high reversible capacities of ca. 530 mA h g(-1) and 380 mA h g(-1) are retained at 5 C and 10 C, respectively. This type of double-layer graphene is expected to be an important platform that will enable the investigation of stabilized three-dimensional topological porous systems and demonstrate the potential of unstacked graphene materials for advanced energy storage, environmental protection, nanocomposite and healthcare applications.