Taming interfacial electronic effects on Pt nanoparticles modulated by their concomitants has emerged as an intriguing approach to optimize Pt catalytic performance. Here, we report Pt nanoparticles assembled on vacancy-abundant hexagonal boron nitride nanosheets and their use as a model catalyst to embrace an interfacial electronic effect on Pt induced by the nanosheets with N-vacancies and B-vacancies for superior CO oxidation catalysis. Experimental results indicate that strong interaction exists between Pt and the vacancies. Bader charge analysis shows that with Pt on B-vacancies, the nanosheets serve as a Lewis acid to accept electrons from Pt, and on the contrary, when Pt sits on N-vacancies, the nanosheets act as a Lewis base for donating electrons to Pt. The overall-electronic effect demonstrates an electron-rich feature of Pt after assembling on hexagonal boron nitride nanosheets. Such an interfacial electronic effect makes Pt favour the adsorption of O2, alleviating CO poisoning and promoting the catalysis.

We used periodic DFT calculations to investigate the effect of alkali promoter on the selectivity of the water‐gas shift reaction (WGSR) explicitly on the Ni(1 1 1) surface. On clean Ni(1 1 1), the WGSR redox and carboxyl pathways are both kinetically competitive. The selectivity of the WGSR can be affected by methanation on Ni, in which the C−O bond cleavage pathway of CHO is the most competitive. A Ni(1 1 1) surface modified with K adatoms was used to further understand the promoter effects on the WGSR selectivity. A combined energetic and kinetic analysis from DFT calculations indicates that the K adatom stabilizes certain reactive intermediates (e.g., H2O, CO) thermodynamically but is energetically neutral or even repulsive toward other intermediates. As a result, WGSR pathways benefit from the presence of K adatoms compared to the competing methanation pathway. This study thus confirmed the promoting effects of alkali metals on the WGSR with DFT‐based mechanistic insights.

Conventional electrolytes made by mixing simple Mg 2+ salts and aprotic solvents, analogous to those in Li-ion batteries, are incompatible with Mg anodes because Mg metal readily reacts with such electrolytes, producing a passivation layer which blocks Mg 2+ transport.Here, we report that, through tuning a conventional electrolyte-Mg(TFSI) 2 (TFSIis N(SO 2 CF 3 ) 2 -) with an Mg(BH 4 ) 2 additive, highly reversible Mg plating/stripping with a high coulombic efficiency is achieved, by neutralizing the first solvation shell of Mg cationic clusters between Mg 2+ and TFSIand enhanced reductive stability of free TFSI -. A critical adsorption step between Mg 0 atoms and active Mg cation clusters involving BH 4 anions is identified to be the key enabler for reversible Mg plating/stripping through analysis of distribution of relaxation times (DRT) from operando electrochemical impedance spectroscopy (EIS), operando electrochemical X-ray absorption spectroscopy (XAS), nuclear magnetic resonance (NMR), and density functional theory (DFT) calculations. This study suggests a new approach for developing advanced electrolytes for Mg batteries and provides a set of in-operando analysis tools for probing electrified Mg/electrolyte interfaces.

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Density functional theory (DFT) calculations were used to investigate the effect of Ni dopants on the removal of chemisorbed oxygen (O*) from the Mo-terminated (T Mo ) and C-terminated (T C ) Mo 2 C(001) surfaces. The removal of adsorbed oxygen from the catalytic site is essential to maintain the long-term activity and selectivity of the carbide catalysts in the deoxygenation process related to bio-oil stabilization and upgrading. In this contribution, the computed reaction energetics and reaction barriers of O* removal were compared among undoped and Ni-doped Mo 2 C(001) surfaces. The DFT calculations indicate that selected Ni-doped surfaces such as Ni adsorbed on T Mo and T C Mo 2 C(001) surfaces enable weaker binding of important reactive intermediates (O*, OH*) compared to the undoped counterparts, which is beneficial for the O* removal from the catalyst surface. This study thus confirms the promoting effect of the Ni dopant on O* removal reaction on the T Mo Mo 2 C(001) and T C Mo 2 C(001) surfaces. This computational prediction has been confirmed by the temperature-programmed reduction profiles of Mo 2 C and Ni-doped Mo 2 C catalysts, which had been passivated and stored in an oxygen environment.

Catalytic dehydrogenation and C−C and C−O bond cleavage for glycerol decomposition on bimetallic Pt−Mo alloy model catalysts are studied using periodic density functional theory. The scaling relationship developed for monometallic systems for fast binding energy prediction has been tested and validated on both Ptskin and Pt 3 Mo-skin bimetallic surfaces. Using only the binding energies of atomic C and O for corresponding alloy surfaces, this simple relationship is shown to be an extremely efficient approach to speeding up the catalytic trend analysis for bimetallic alloy catalysts. Similar to Pt(111), it is found that the Pt-skin surface also favors dehydrogenation via C−H bond cleavage and faster C−C bond cleavage over C−O bond cleavage, but the overall activity decreases compared with pure Pt. On Pt 3 Mo-skin surfaces, the overall reaction becomes much more exothermic, but Mo species significantly affect the selectivity by favoring the C−O bond cleavage. Thermodynamic analyses also predict that surface Mo species can be easily oxidized under typical reforming conditions, forming molybdate clusters and severely altering surface structures and potentially catalytic properties. Guided by experimental observations, this study also explores possible bifunctional characteristics for Pt−Mo bimetallic catalysts responsible for improved reforming activity and hydrogen production rates.

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The selective production of C3+ olefins from renewable feedstocks, especially via C1 and C2 platform chemicals, is a critical challenge for obtaining economically viable low-carbon middle-distillate transportation fuels (i.e., jet and diesel). Here, we report a multifunctional catalyst system composed of Zn–Y/Beta and “single-atom” alloy (SAA) Pt–Cu/Al2O3, which selectively catalyzes ethanol-to-olefin (C3+, ETO) valorization in the absence of cofed hydrogen, forming butenes as the primary olefin products. Beta zeolites containing predominately isolated Zn and Y metal sites catalyze ethanol upgrading steps (588 K, 3.1 kPa ethanol, ambient pressure) regardless of cofed hydrogen partial pressure (0–98.3 kPa H2), forming butadiene as the primary product (60% selectivity at an 87% conversion). The Zn–Y/Beta catalyst possesses site-isolated Zn and Y Lewis acid sites (at ∼7 wt % Y) and Brønsted acidic Y sites, the latter of which have been previously uncharacterized. A secondary bed of SAA Pt–Cu/Al2O3 selectively hydrogenates butadiene to butene isomers at a consistent reaction temperature using hydrogen generated in situ from ethanol to butadiene (ETB) conversion. This unique hydrogenation reactivity at near-stoichiometric hydrogen and butadiene partial pressures is not observed over monometallic Pt or Cu catalysts, highlighting these operating conditions as a critical SAA catalyst application area for conjugated diene selective hydrogenation at high reaction temperatures (>573 K) and low H2/diene ratios (e.g., 1:1). Single-bed steady-state selective hydrogenation rates, associated apparent hydrogen and butadiene reaction orders, and density functional theory (DFT) calculations of the Horiuti–Polanyi reaction mechanisms indicate that the unique butadiene selective hydrogenation reactivity over SAA Pt–Cu/Al2O3 reflects lower hydrogen scission barriers relative to monometallic Cu surfaces and limited butene binding energies relative to monometallic Pt surfaces. DFT calculations further indicate the preferential desorption of butene isomers over SAA Pt–Cu(111) and Cu(111) surfaces, while Pt(111) surfaces favor subsequent butene hydrogenation reactions to form butane over butene desorption events. Under operating conditions without hydrogen cofeeding, this combination of Zn–Y/Beta and SAA Pt–Cu catalysts can selectively form butenes (65% butenes, 78% C3+ selectivity at 94% conversion) and avoid butane formation using only in situ-generated hydrogen, avoiding costly hydrogen cofeeding requirements that hinder many renewable energy processes.