Bin Wang

The electrochemical oxidation of alcohols is a promising alternative anodic reaction to the kinetically slow oxygen evolution reaction in water electrolysis while also enabling the production of value-added chemicals. Here, we investigate how para-substituents influence the electrochemical oxidation of benzyl alcohol derivatives on gold (Au) electrodes in alkaline media. Benzyl alcohol (BA), 4-methoxybenzyl alcohol (4-MBA), and 4-(hydroxymethyl)benzoic acid (4-HMBA) were examined using cyclic voltammetry, chronoamperometry coupled with high-performance liquid chromatography (HPLC), electrochemical quartz crystal microbalance (EC-QCM) measurements, Raman spectroscopy, and density functional theory (DFT) calculations. Voltammetric measurements show broadly similar oxidation behavior for BA and 4-MBA, whereas 4-HMBA exhibits a substantially suppressed oxidation response. EC-QCM measurements further demonstrate that the three substrate molecules alter the oxidation and reduction behavior of the Au surface to different extents, indicating a strong coupling between molecular adsorption and surface redox dynamics. DFT calculations show that all three molecules preferentially adopt a ring-flat adsorption geometry on the Au(111) surface, but para-substitution changes the orientation of the benzylic alcohol group relative to the surface. BA places the reactive benzylic C–H bond closest to the Au surface and exhibits the longest calculated benzylic C–H bond within the computational model, providing a possible structural descriptor for the substrate-dependent electrochemical behavior. In contrast, the deprotonated carboxylate form of 4-HMBA binds strongly to Au and may reduce active-site availability. Increasing alkalinity generally enhances alcohol oxidation, although the response is substrate dependent. Together, these results show that the oxidation of para-substituted benzyl alcohols on Au is governed by the interplay among substrate speciation, adsorption geometry, benzylic C–H orientation, and substrate-induced changes in Au surface redox behavior rather than by substituent electronic effects alone.

Ti3C2Tx MXenes are emerging plasmonic materials whose tunable surface terminations provide a route for plasmon engineering. However, termination-dependent plasmonic properties of Ti3C2Tx remain largely unexplored. Using real-time time-dependent density functional theory, we investigate plasmon excitations and hot-carrier generation in Ti3C2Tx terminated by O, F, Cl, and OH. Surface terminations regulate the plasmonic response, leading to distinct energy distributions and spatial localization of hot carriers in Ti3C2Tx. In Ti3C2O2, the highly oxidized Ti drives spatial separation of hot holes and electrons, potentially suppressing their recombination. Ti3C2F2, Ti3C2Cl2, and Ti3C2(OH)2 instead show similar carrier localization, reflecting their comparable electronic structures. Notably, Ti3C2(OH)2 exhibits a larger hot-carrier population, consistent with its greater absorbed energy under the selected excitation conditions. These findings establish surface termination engineering as a strategy for controlling plasmonic hot carriers in MXenes, with implications for plasmon-driven applications.

Carbon electrodes are ubiquitous in organic electrochemistry, yet the structural origin of their selectivity in radical‐mediated reactions remains poorly understood. Here, we show that carbon microstructure is a primary determinant of product selectivity in Kolbe electrolysis, a prototypical electrochemical C─C coupling reaction central to fuel, fine chemical, and pharmaceutical production. We investigated eight carbon electrodes in two complementary libraries: five commercial carbons spanning diverse macroarchitectures, and carbon nanofibers with controlled graphitization. Both reveal a consistent structure–selectivity trend for various carboxylic acids and a mixed‐acid feed. Counterintuitively, the most disordered electrodes, despite the highest charge‐transfer resistance, give about an order of magnitude more Kolbe dimer than highly graphitized ones, which give little or none. Disordered, sp ³ ‐rich surfaces bearing oxygen functionalities strongly favor both Kolbe coupling (alkane) and Hofer–Moest products (alcohol/aldehyde), whereas graphitized, sp ² ‐rich surfaces favor further oxidation to carbocations, yielding mainly alkenes and esters. Density functional theory calculations suggest that oxygen‐functionalized sites bind the alkyl radical about three times more strongly than pristine graphene, consistent with longer‐lived surface‐bound radicals that can couple. These findings help rationalize the widely used but poorly understood performance of reticulated vitreous carbon in organic electrosynthesis and offer guiding principles for rational carbon electrode design.

Carbon electrodes are ubiquitous in organic electrochemistry, yet the structural origin of their selectivity in radical‐mediated reactions remains poorly understood. Here, we show that carbon microstructure is a primary determinant of product selectivity in Kolbe electrolysis, a prototypical electrochemical C─C coupling reaction central to fuel, fine chemical, and pharmaceutical production. We investigated eight carbon electrodes in two complementary libraries: five commercial carbons spanning diverse macroarchitectures, and carbon nanofibers with controlled graphitization. Both reveal a consistent structure–selectivity trend for various carboxylic acids and a mixed‐acid feed. Counterintuitively, the most disordered electrodes, despite the highest charge‐transfer resistance, give about an order of magnitude more Kolbe dimer than highly graphitized ones, which give little or none. Disordered, sp ³ ‐rich surfaces bearing oxygen functionalities strongly favor both Kolbe coupling (alkane) and Hofer–Moest products (alcohol/aldehyde), whereas graphitized, sp ² ‐rich surfaces favor further oxidation to carbocations, yielding mainly alkenes and esters. Density functional theory calculations suggest that oxygen‐functionalized sites bind the alkyl radical about three times more strongly than pristine graphene, consistent with longer‐lived surface‐bound radicals that can couple. These findings help rationalize the widely used but poorly understood performance of reticulated vitreous carbon in organic electrosynthesis and offer guiding principles for rational carbon electrode design.

Zeolite Y catalysts contain Brønsted acid sites in accessible large pores, known as supercages, and in sterically inaccessible small pores within sodalite cages. Access to acid sites within sodalite units is precluded due to their 0.26 nm cage windows, which are smaller than the critical diameters of relevant hydrocarbons. By preparing a series of HY catalysts with different acid site densities, including for the first time reported those with theoretical maximum acid site density, the number of acid sites in the inaccessible sodalite cages is shown to be a dominant factor in reactivity for catalysts in which the structural integrity of the sodalite unit is preserved. Using a combination of catalyst preparation, spectroscopy, isotopic exchange measurements with bulky hydrocarbons, and high-temperature isooctane cracking experiments on catalysts with fixed supercage proton amounts but varying sodalite proton concentrations, the dominant contribution of sodalite cage acid sites is quantified. DFT calculations suggest that a plausible mechanism involves framework flexibility in the form of site exchange via rotation of sodalite protons into supercages. In addition to revealing that commonly used acid site density measurements and turnover frequency calculations may exclude contributions from important sites, these data demonstrate that BASs in intact sodalite cages can define and control catalyst reactivity in HY catalysts. Large increases in catalyst activity are obtained by exchanging La³⁺ cations into sodalite cages with maximum acid site densities. These findings extend beyond HY catalysts, as they imply that other zeolite catalysts with sterically occluded acid sites may be tuned for improved performance.

Photoinduced hot electrons are central to plasmon-driven catalysis. Atomically thin Ti₃C₂O₂, with high carrier density and broad optical absorption, offers a promising platform for plasmon-driven reactions. However, comprehensive investigations of its plasmon resonance, hot-carrier generation, and plasmonic catalytic performance remain limited. In this work, real-time time-dependent density functional theory (rt-TDDFT) was employed to study Ti₃C₂O₂’s plasmon excitation and hot-carrier generation from nonradiative plasmon damping. The temporal evolution of the dipole moment reveals plasmon resonance in Ti₃C₂O₂, followed by strong plasmon damping that redistributes the stored energy to generate hot carriers. Ti₃C₂O₂ with low oxygen vacancy concentration (O_v-Ti₃C₂O₂) exhibits plasmonic behavior resembling the pristine surface, and the plasmon-generated hot electrons can markedly reduce the dissociation barrier of CO₂ at the oxygen vacancy. These findings provide fundamental insights into the plasmonic properties of Ti₃C₂O₂ and how they drive its catalytic performance in surface reactions, which is valuable for advancing plasmon-driven catalysis.

In a highly purified host, the coherence of quantum emitters is ultimately limited by hyperfine interactions between the emitter and lattice nuclei possessing non‐zero nuclear magnetic moments. This limitation can only be mitigated through isotopic purification. In this work, we investigate CeO ₂ as a host composed entirely of nuclei with zero nuclear moment. High‐quality CeO ₂ thin films were grown by PLD and doped with Tm and Er ions. Structural characterization using X‐ray diffraction, atomic force microscopy, and ion channeling confirms single‐crystalline, atomically smooth films with dopants substitutionally incorporated at Ce lattice sites. Photoluminescence lifetime measurements show significantly longer lifetimes for Er‐doped CeO ₂ (2.9 – 5.3 ms) compared with Tm‐doped films (14 – 68 µs). Moreover, the Er‐doped PLD films exhibit longer lifetimes at ∼1% dopant concentration than previously reported for MBE‐grown films. Density functional theory calculations reveal a substantial overlap between unoccupied O 2p and Tm 4f states near the valence band maximum, whereas Er 4f states remain well isolated. This electronic interaction likely introduces non‐radiative recombination pathways in Tm‐doped CeO ₂ , explaining the reduced lifetimes. These findings highlight the importance of selecting appropriate dopant‐host combinations and optimized growth conditions to minimize non‐radiative channels for quantum applications.

Water-assisted proton shuttling at a bifunctional metal-acid interface promotes hydrogenation of CC bonds in a cyclohexene molecule.

Efficient carbon capture and utilization require strategies that minimize energy penalties of CO₂ regeneration and compression. Reactive capture and conversion (RCC) address this challenge by integrating capture with direct electrochemical conversion. Here, we show an NH₃-mediated tandem RCC system that couples capture of CO₂ from simulated flue gas (10% v/v CO₂ in N₂) with electroreduction of NH₄HCO₃ to CO over a Ni single-atom catalyst (Ni-SAC). Speciation modeling and capture experiments revealed that a deep CO₂ capture with C/N ratio of 0.65 was achieved using 2.5 M NH₃ from simulated flue gas. Electrolysis of the resulting NH₄HCO₃ on the Ni-SAC delivered an 85% CO Faradaic efficiency at 100 mA/cm² with excellent tolerance to NH₃/NH₄ ⁺ as confirmed by DFT calculations and ab initio molecular dynamics (AIMD) simulations. Further, the techno-economic analysis established a levelized total cost of CO manufacturing of $25.43/kmol, gauging the practical viability. Overall, this study holds great potential to decarbonize the chemical manufacturing industry while reducing synthetic production costs.