Phase Interface Engineering of Cu1Co Single Atom Alloy Catalysts for Enhanced Hydrogen Production from Methanol Decomposition.

Direct utilization of crude and waste H2 via CO-tolerant hydrogenation

Ethane dehydrogenation over the single-atom alloy catalysts: Screening out the excellent catalyst with the dual descriptors

Selective hydrogenation of α,β-unsaturated aldehydes to produce unsaturated alcohols remains a challenge in catalysis. Here, we explore, on the basis of first-principles simulations, single-atom alloy (SAA) catalysts on copper as a class of catalytic materials to enhance the selectivity for C═O bond hydrogenation in unsaturated aldehydes by controlling the binding strength of the C═C and C═O bonds. We show that on SAA of early transition metals such as Ti, Zr, and Hf, the C═O binding mode of acrolein is favored but the strong binding renders subsequent hydrogenation and desorption impossible. On SAA of late-transition metals, on the other hand, the C═C binding mode is favored and C═C bond hydrogenation follows, resulting in the production of undesired saturated aldehydes. Mid-transition metals (Cr and Mn) in Cu(111) appear as the optimal systems, since they favor acrolein adsorption via the C═O bond but with a moderate binding strength, compatible with catalysis. Additionally, acrolein migration from the C═O to the C═C binding mode, which would open the low energy path for C═C bond hydrogenation, is prevented by a large barrier for this process. SAA of Cr in Cu appears as an optimal candidate, and kinetic simulations show that the selectivity for propenol formation is controlled by preventing the acrolein migration from the more stable C═O to the less stable C═C binding mode and subsequent H-migration and by the formation of the O-H bond from the monohydrogenated intermediate. Dilute alloy catalysts therefore enable tuning the binding strength of intermediates and transition states, opening control of catalytic activity and selectivity.

In reactions of hydrodeoxygenation (HDO) of biomass-derived chemicals, one promising method for improving the yield of desirable products is to control the crystal phase of the catalyst and thus the adsorption configuration of intermediates. In this work, we have investigated the catalytic activity and selectivity of Pt1Co single-atom alloy (SAA) catalysts with fcc (face-centered cubic) and hcp (hexagonal close-packed) cobalt crystal phases toward 5-hydroxymethylfurfural (5-HMF) HDO reaction by density functional theory (DFT) calculation. Potential energy profiles of 5-HMF HDO reactions on the Pt1Co-fcc and Pt1Co-hcp surfaces show that the Pt1Co-hcp surface has a lower hydrogenation energy barrier (0.96 and 0.83 eV) and C–O bond cleavage energy barrier (0.58 and 0.44 eV) than the Pt1Co-fcc surface, indicating the Pt1Co-hcp surface exhibits higher catalytic activity. Ring-opening energy and ring hydrogenation calculations distinguish product selectivity: the optimal product on the Pt1Co-hcp surface is 2,5-dimethyltetrahydrofuran (DHMF), but 2-hexanol on the Pt1Co-fcc surface, which is caused by atomic density difference from the crystalline phase. This work provides a new theoretical support to improve reaction activity and product selectivity by controlling the crystal phase of biomass HDO catalysts.

The propane dehydrogenation (PDH) reaction converts cheap propane to value-added propene. Pt-based catalysts show high performance in PDH, but suffer from coke formation and deactivation. Therefore, promoter, that is, a second metal component, is required to enhance its stability. Our previous study has constructed Pt/Cu single atom alloy (SAA) catalysts and achieved high PDH selectivity and anticoke ability. However, the nature of its high performance in PDH still remains to be revealed. This paper describes the origin of catalytic performance for Pt/Cu SAA in PDH via density functional theory (DFT) calculations and kinetic Monte Carlo (kMC) simulations. We constructed a complex reaction network with 54 reversible reaction steps, including adsorption, desorption, C–H bond breaking, and C–C bond cracking processes on the Pt/Cu SAA catalyst. The high selectivity of propene has been demonstrated because of the higher occurrence of propene formation and, simultaneously, the high energy barriers for deep dehydrogenation of propene. The lower coverages of the coke species origin from the deep dehydrogenation instead of the C–C bond cracking for Pt/Cu SAA catalyst, which is different from that proposed for Pt catalyst. The simulation suggests that hydrogen (H2) cofeeding can further reduce the surface coke species. Overall, the current study provides fundamental insights into the origin of high selectivity and anticoke ability to help the design of stable and high-performance Pt-based catalysts.

Selective hydrogenolysis of biomass-derived glycerol to propanediol is an important reaction to produce high value-added chemicals but remains a big challenge. Herein we report a PtCu single atom alloy (SAA) catalyst with single Pt atom dispersed on Cu nanoclusters, which exhibits dramatically boosted catalytic performance (yield: 98.8%) towards glycerol hydrogenolysis to 1,2-propanediol. Remarkably, the turnover frequency reaches up to 2.6 × 103 molglycerol·molPtCu–SAA−1·h−1, which is to our knowledge the largest value among reported heterogeneous metal catalysts. Both in situ experimental studies and theoretical calculations verify interface sites of PtCu–SAA serve as intrinsic active sites, in which the single Pt atom facilitates the breakage of central C–H bond whilst the terminal C–O bond undergoes dissociation adsorption on adjacent Cu atom. This interfacial synergistic catalysis based on PtCu–SAA changes the reaction pathway with a decreased activation energy, which can be extended to other noble metal alloy systems.

To solve the safety problems and economic inefficiency of transporting and storing gaseous hydrogen, developing efficient catalytic decomposition of liquid organic hydrogen carriers for in situ hydrogen production is attracting more and more attention. Here, a series of Cr-doped, Mn-promoted Cu-based catalysts for methanol decomposition were fabricated from quaternary Cu–Mn–Cr–Al layered double hydroxides. It was demonstrated that Mn incorporation promoted the reduction and dispersion of copper species and regulated the electronic properties of surface metallic Cu sites, and an appropriate amount of Cr doping facilitated the generation of smaller Cu particles and reduced the surface acidity over catalysts, thereby favoring the construction of generous interfacial Cu+ sites in the form of Cu+–Ov–Mn and Cu+–O–M structures (Ov: oxygen vacancy; M = Mn or Cr). The Cu-based catalyst bearing a Cr:Mn molar ratio of 0.4 achieved a high hydrogen selectivity of 84.3% at complete methanol conversion, along with long-term stability during 80 h of reaction. Through various exhaustive characterization studies, in situ diffuse reflectance infrared Fourier transform spectra of methanol adsorption and desorption, and density functional theory calculations, it was revealed that abundant interfacial Cu+–Ov–Mn and Cu+–O–M structures and favorable Cu+–Cu0 synergistic effects in Cu-based catalysts efficiently promoted a series of dehydrogenation processes of methanol and reaction intermediates, thus boosting hydrogen production. This study provides effective methods for the construction of Cu-based catalysts by engineering surficial and interfacial sites conducive to the efficient hydrogen production through methanol decomposition.

Methane decomposition using single-atom alloy (SAA) catalysts, known for uniform active sites and high selectivity, significantly enhances hydrogen production efficiency without CO2 emissions. This study introduces a comprehensive database of C-H dissociation energy barriers on SAA surfaces, generated through machine learning (ML) and density functional theory (DFT). First-principles DFT calculations were utilized to determine dissociation energy barriers for various SAA surfaces, and ML models were trained on these results to predict energy barriers for a wide range of SAA surface compositions. The resulting dataset, comprising 10,950 entries with descriptors and energy barriers, as main predictive outcomes, has been validated against existing DFT calculations confirming the reliability of the ML predictions. This dataset provides valuable insights into the catalytic mechanisms of SAAs and supports the development of efficient, low-emission hydrogen production technologies. All data and computational tools are publicly accessible for further advancements in catalysis and sustainable energy solutions.

The catalytic behavior of alloy electrocatalyst is strongly influenced by host–guest metal interaction, which governs adsorption energy and product selectivity. However, in conventional bimetallic alloy systems, the catalyst composition and the geometric configuration often obscure the identification of critical active sites. Here, we investigate the host–guest metal interaction in Cu–In single atom alloy (SAA) catalysts, demonstrating a remarkable switching of electrochemical CO2 reduction reaction (CO2RR) pathway. Doping 1% Indium into a Cu matrix forms isolated In‐Cu interfaces, enabling efficient CO2‐to‐CO conversion with a Faradaic efficiency exceeding 90%. Conversely, doping 1% Cu into an Indium matrix leads to the formation of a CuIn alloy phase, shifting the product selectivity to HCOOH with a Faradaic efficiency exceeding 90%. In situ spectroscopic measurements and density functional theory (DFT) simulations reveal that Cu serves as the active site on both Cu–In SAA catalysts. The adsorption energy of host Cu atoms is affected by doped Indium at the In‐Cu interface, which promotes CO2 adsorption and activation while weakening the binding strength of linearly bonded *CO, thereby enhancing CO selectivity. Conversely, the rigid matrix of the CuIn alloy stabilizes the bridge‐bonded *CO, favoring the production of HCOOH.

Single-atom alloy with Pt-Co dual sites as an efficient electrocatalyst for oxygen reduction reaction

Regulating the location relationship between Cu nanoparticles and Pt atoms to enhance the catalytic hydroisomerization performance: Together or apart?

In recent years, single-atom alloy catalysts (SAAs) have received much attention due to the combination of structural features of both single-atom and alloy catalysts, as well as their efficient catalytic activity, high selectivity, and high stability in various chemical reactions. In this work, we designed a series of Cu-based SAAs by doping isolated 3d transition metal (TM1) atoms on the surface of Cu(111) (TM1 = Fe, Co, Ru, Rh, Os and Ir), in which Ir1/Cu(111) SAAs are considered to be the most stable among 3d-series SAAs due to their optimal binding energy (Eb). The density of states of SAAs have been systematically investigated to further discuss structural properties. Based on density functional theory calculations, the activity and selectivity of Ir1/Cu(111) SAAs are investigated for electrocatalytic CO2 reduction reaction (CO2RR). The initial hydrogenation of CO2 on Ir1/Cu(111) SAAs can form *CO intermediates, which will be further to CH4 production by the pathway of *CO → *CHO → *CHOH → *CH2OH → *CH2 → *CH3 → CH4. This study provides theoretical insights for the rational design of selective Cu-based monatomic alloy catalysts.

The Pt–Cu single-atom alloy (SAA) catalyst showed significantly enhanced activity, selectivity, and stability for the hydrogenolysis of methyl glycolate to ethanol.

A comprehensive study of the kinetics of the catalytic hydrogenation of unsaturated aldehydes, in particular of cinnamaldehyde, promoted by CuPtx/SBA-15 single-atom alloy catalysts was carried out ...

Discovery of single-atom alloy catalysts for CO2-to-methanol reaction by density functional theory calculations