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Reducing the ever-growing level of CO2 in the atmosphere is critical for the sustainable development of human society in the context of global warming. Integration of the capture and upgrading of CO2 is, therefore, highly desirable since each process step is costly, both energetically and economically. Here, we report a CO2 direct air capture (DAC) and fixation process that produces methane. Low concentrations of CO2 (∼400 ppm) in the air are captured by an aqueous solution of sodium hydroxide to form carbonate. The carbonate is subsequently hydrogenated to methane, which is easily separated from the reaction system, catalyzed by TiO2-supported Ru in the aqueous phase with a selectivity of 99.9% among gas-phase products. The concurrent regenerated hydroxide, in turn, increases the alkalinity of the aqueous solution for further CO2 capture, thereby enabling this one-of-its-kind continuous CO2 capture and methanation process. Engineering simulations demonstrate the energy feasibility of this CO2 DAC and methanation process, highlighting its promise for potential large-scale applications.

Single-site pincer-ligated iridium complexes exhibit the ability for C-H activation in homogeneous catalysis. However, instability and difficulty in catalyst recycling are inherent disadvantages of the homogeneous catalyst, limiting its development. Here, we report an atomically dispersed Ir catalyst as the bridge between homogeneous and heterogeneous catalysis, which displays an outstanding catalytic performance for n-butane dehydrogenation, with a remarkable n-butane reaction rate (8.8 mol·gIr−1·h−1) and high butene selectivity (95.6%) at low temperature (450 °C). Significantly, we correlate the BDH activity with the Ir species from nanoscale to sub-nanoscale, to reveal the nature of structure-dependence of catalyst. Moreover, we compare Ir single atoms with Pt single atoms and Pd single atoms for in-depth understanding the nature of metal-dependence at the atomic level. From experimental and theoretical calculations results, the isolated Ir site is suitable for both reactant adsorption/activation and product desorption. Its remarkable dehydrogenation capacity and moderate adsorption behavior are the key to the outstanding catalytic activity and selectivity. © 2023, The Author(s).

Nanozyme has attracted great attention due to its diverse enzymatic catalytic activities. But there are still challenges in constructing novel nanozyme with robust catalytic activity. Here, we report an atomically dispersed and fully exposed Cu3 cluster stabilized on defect-rich nanodiamond-graphene hybrid support (Cu3/ND@G) with unique active adsorption sites, which benefit the adsorption and cleavage of O2, resulting in enhanced oxidase-like and antibacterial activity. The catalytic rate constant of Cu3/ND@G (Kcat = 1.474 × 10−1 s−1) is higher than those of previously reported copper single atom oxidase mimics (0.5 × 10−3 s−1) and even the commercial Pt/C mimics (1.01 × 10−2 s−1). DFT calculation revealed that the atomically dispersed Cu3 cluster as active center significantly improves the oxidase-like activity, attributing to the easy dissociation of O2 into reactive oxygen species (•OH). The atomically dispersed Cu3 cluster with an antibacterial rate of 100% in the NaAc buffer presents its potential application in the field of antibacterial materials. © 2021

Atomically dispersed Pd (Pd1) catalysts supported on annealed nanodiamond were prepared through a deposition–precipitation method toward propane direct dehydrogenation (PDDH). The Pd1 catalyst is superior to Pd cluster/particle catalysts in activity and stability. Combining experimental characterizations and DFT calculations revealed that atomically dispersed Pd species have strong interactions with the hybrid nanodiamond/graphene support, leading to better resistance to coke formation. More importantly, Pd sintering is inevitable in the cluster/particle catalysts, while the high dispersion of Pd species in Pd1 catalyst is well-preserved during the reaction, which is caused in part by the redistribution or migration of Pd single atoms onto the carbonaceous compound (coke). As a result, the Pd1 catalyst shows significantly better activity and stability in high-reaction temperatures than Pd cluster/particle catalysts. This work reveals deeper insights on designing highly dispersed metal catalysts with the ability of in situ regeneration of active sites in high-temperature catalytic reactions. © 2022 American Chemical Society

Nanozyme has attracted great attention due to its diverse enzymatic catalytic activities. But there are still challenges in constructing novel nanozyme with robust catalytic activity. Here, we report an atomically dispersed and fully exposed Cu3 cluster stabilized on defect-rich nanodiamond-graphene hybrid support (Cu3/ND@G) with unique active adsorption sites, which benefit the adsorption and cleavage of O2, resulting in enhanced oxidase-like and antibacterial activity. The catalytic rate constant of Cu3/ND@G (Kcat = 1.474 × 10−1 s−1) is higher than those of previously reported copper single atom oxidase mimics (0.5 × 10−3 s−1) and even the commercial Pt/C mimics (1.01 × 10−2 s−1). DFT calculation revealed that the atomically dispersed Cu3 cluster as active center significantly improves the oxidase-like activity, attributing to the easy dissociation of O2 into reactive oxygen species (•OH). The atomically dispersed Cu3 cluster with an antibacterial rate of 100% in the NaAc buffer presents its potential application in the field of antibacterial materials. © 2021

A fundamental understanding of the active sites in heterogeneous catalysts is extremely important in the development of effective catalysts. In general, it is difficult to identify the catalytically active sites due to their structural complexity, including the size and specific atomic configurations. In this paper, we prepare different Pt species (single atoms, fully exposed clusters, and nanoparticles) on a nanodiamond/graphene (ND@G) hybrid support to understand their evolution in structure for low-temperature CO oxidation. Remarkably, the atomically dispersed and fully exposed Pt clusters with an ensemble of a few Pt atoms showed the maximum atom utilization of low-coordinated metal sites. As determined by a catalytic performance evaluation, detailed characterizations, and theoretical calculations, the 0.5 wt % Ptn/ND@G catalyst showed a catalytic performance for CO oxidation at low temperature superior to those of single-atom and nanoparticle catalysts, which was attributed to the weakened CO adsorption and facilitated O2 dissociative adsorption on these atomically dispersed and fully exposed Pt cluster catalysts. © 2022 American Chemical Society.

Atomically dispersed Pd (Pd1) catalysts supported on annealed nanodiamond were prepared through a deposition–precipitation method toward propane direct dehydrogenation (PDDH). The Pd1 catalyst is superior to Pd cluster/particle catalysts in activity and stability. Combining experimental characterizations and DFT calculations revealed that atomically dispersed Pd species have strong interactions with the hybrid nanodiamond/graphene support, leading to better resistance to coke formation. More importantly, Pd sintering is inevitable in the cluster/particle catalysts, while the high dispersion of Pd species in Pd1 catalyst is well-preserved during the reaction, which is caused in part by the redistribution or migration of Pd single atoms onto the carbonaceous compound (coke). As a result, the Pd1 catalyst shows significantly better activity and stability in high-reaction temperatures than Pd cluster/particle catalysts. This work reveals deeper insights on designing highly dispersed metal catalysts with the ability of in situ regeneration of active sites in high-temperature catalytic reactions. © 2022 American Chemical Society

Hydrogen is increasingly being discussed as clean energy for the goal of net-zero carbon emissions, applied in the proton-exchange-membrane fuel cells (PEMFC). The preferential oxidation of CO (PROX) in hydrogen is a promising solution for hydrogen purification to avoid catalysts from being poisoned by the trace amount of CO in hydrogen-rich fuel gas. Here, we report the fabrication of a novel bimetallic Pt-Fe catalyst with ultralow metal loading, in which fully-exposed Pt clusters bonded with neighbor atomically dispersed Fe atoms on the defective graphene surface. The fully-exposed PtFe cluster catalyst could achieve complete elimination of CO through PROX reaction and almost 100% CO selectivity, while maintaining good stability for a long period. It has the mass-specific activity of 6.19 (molCO)*(gPt)−1*h−1 at room temperature, which surpasses those reported in literatures. The exhaustive experimental results and theoretical calculations reveal that the construction of fully-exposed bimetallic Pt-Fe cluster catalysts with maximized atomic efficiency and abundant interfacial sites could facilitate oxygen activation on unsaturated Fe species and CO adsorption on electron-rich Pt clusters to hence the probability of CO oxidation, leading to excellent reactivity in practical applications. © 2022, The Author(s).

The atomically dispersed metal catalyst or single-atom catalyst (SAC) with the utmost metal utilization efficiency shows excellent selectivity toward ethylene compared to the metal nanoparticles catalyst in the acetylene semi-hydrogenation reaction. However, these catalysts normally work at relatively high temperatures. Achieving low-temperature reactivity while preserving high selectivity remains a challenge. To improve the intrinsic reactivity of SACs, rationally tailoring the coordination environments of the first metal atom by coordinating it with a second neighboring metal atom affords an opportunity. Here, we report the fabrication of a dual-atom catalyst (DAC) that features a bonded Pd1-Cu1atomic pair anchoring on nanodiamond graphene (ND@G). Compared to the single-atom Pd or Cu catalyst, it exhibits increased reactivity at a lower temperature, with 100% acetylene conversion and 92% ethylene selectivity at 110 °C. This work provides a strategy for designing DACs for low-temperature hydrogenation by manipulating the coordination environment of catalytic sites at the atomic level. © 2022 American Chemical Society. All rights reserved.

Nanozyme has attracted great attention due to its diverse enzymatic catalytic activities. But there are still challenges in constructing novel nanozyme with robust catalytic activity. Here, we report an atomically dispersed and fully exposed Cu3 cluster stabilized on defect-rich nanodiamond-graphene hybrid support (Cu3/ND@G) with unique active adsorption sites, which benefit the adsorption and cleavage of O2, resulting in enhanced oxidase-like and antibacterial activity. The catalytic rate constant of Cu3/ND@G (Kcat = 1.474 × 10−1 s−1) is higher than those of previously reported copper single atom oxidase mimics (0.5 × 10−3 s−1) and even the commercial Pt/C mimics (1.01 × 10−2 s−1). DFT calculation revealed that the atomically dispersed Cu3 cluster as active center significantly improves the oxidase-like activity, attributing to the easy dissociation of O2 into reactive oxygen species (•OH). The atomically dispersed Cu3 cluster with an antibacterial rate of 100% in the NaAc buffer presents its potential application in the field of antibacterial materials. © 2021

The pursuit of energy conservation and environmental protection has always been a hot topic in the catalytic fields, which is inseparable from the rational designing of efficient catalysts and an in-depth understanding of the catalytic reaction mechanism. In this work, fully-exposed Pt clusters were fabricated on the atomically dispersed Sn decorated nanodiamond/graphene (Sn-ND@G) hybrid support and employed for direct dehydrogenation (DDH) of ethylbenzene (EB) to styrene (ST). The detailed structural characterizations revealed the fully-exposed Pt clusters were stabilized on Sn-ND@G, assisted by the spatial separation of atomically dispersed Sn species. The as-prepared Pt/Sn-ND@G catalyst showed enhanced ST yield (136.2 molEB·molPt−1·h−1 EB conversion rate and 99.7% ST selectivity) and robust long-term stability at 500 °C for the EB DDH reaction, compared with the traditional ND@G supported Pt nanoparticle catalyst (Pt/ND@G). The ST prefers to desorb from the fully-exposed Pt clusters, resulting in the enhanced DDH catalytic performance of the Pt/Sn-ND@G catalyst. The present work paves a new way for designing highly dispersed and stable supported metal catalysts for DDH reactions. [Figure not available: see fulltext.] © 2022, Tsinghua University Press.

Atomically dispersed metal catalysts (ADMCs), which offer maximized atom-use efficiency and catalytic performance enhancements for many catalytic systems, have received increasing attention in the catalysis field. Additionally, ADMCs with well-defined architectures are promising for providing valuable information to derive structure-performance relationships. Here, we immobilized Cu1 on a defective nanodiamond-graphene (ND@G) and N-doped nanodiamond-graphene (ND@NG). By changing the coordination environments (Cu-C or Cu-N), the electronic state of Cu ADMCs can be tailored. The highly oxidized Cu atoms in Cu-N AMDCs present distinctively different acetylene hydrogenation activity compared to that in Cu-C AMDCs (i.e., with high conversion (100%), high selectivity (93%), and good stability (more than for 100 h)). Density functional theory and H2-D2 exchange experiments reveal that Cu-C bond anchoring favors H2 dissociative adsorption, which is a rate-limiting step. In addition, the facile desorption of the target product C2H4 over Cu-C ADMCs ensures the outstanding activity and selectivity of the catalyst. This work thus helps to bring perspectives for linking activity and structures of ADMCs and designing active ADMCs for hydrogenation applications. © 2021 American Chemical Society.

Exploring antibacterial nanomaterials with excellent catalytic antibacterial properties has always been a hot research topic. However, the construction of nanomaterials with robust antibacterial activity at the atomic level remains a great challenge. Here a fully-exposed Pd cluster atomically-dispersed on nanodiamond-graphene (Pd-n/ND@G) with excellent catalytic antibacterial properties is reported. The fully-exposed Pd cluster nanozyme provides atomically-dispersed Pd cluster sites that facilitate the activation of oxygen. Notably, the oxidase-like catalytic performance of the fully-exposed Pd cluster nanozyme is much higher than that of Pd single-atom oxidase mimic, Pd nanoparticles oxidase mimic and even the previously reported palladium-based oxidase mimics. Under the density functional theory (DFT) calculations, the Pd cluster sites can efficiently catalyze the decomposition of oxygen to generate reactive oxygen species, resulting in strong antibacterial properties. This research provides a valuable insight to the design of novel oxidase mimic and antibacterial nanomaterial.

The product selectivity in catalytic hydrogenation of nitriles is strongly correlated with the structure of the catalyst. In this work, two types of atomically dispersed Pd species stabilized on the defect-rich nanodiamond-graphene (ND@G) hybrid support: single Pd atoms (Pd1/ND@G) and fully exposed Pd clusters with average three Pd atoms (Pdn/ND@G), were fabricated. The two catalysts show distinct difference in the catalytic transfer hydrogenation of nitriles. The Pd1/ND@G catalyst preferentially generates secondary amines (Turnover frequency (TOF@333 K 709 h−1, selectivity >98%), while the Pdn/ND@G catalyst exhibits high selectivity towards primary amines (TOF@313 K 543 h−1, selectivity >98%) under mild reaction conditions. Detailed characterizations and density functional theory (DFT) calculations show that the structure of atomically dispersed Pd catalysts governs the dissociative adsorption pattern of H2 and also the hydrogenation pathway of the benzylideneimine (BI) intermediate, resulting in different product selectivity over Pd1/ND@G and Pdn/ND@G, respectively. The structure-performance relationship established over atomically dispersed Pd catalysts provides valuable insights for designing catalysts with tunable selectivity. © 2021, The Author(s).

Direct dehydrogenation of alkanes is of great interest but presents a significant challenge in activating C-H bond at a low temperature. Here, we report fully exposed Pd clusters consisting of an average of three Pd atoms on a hybrid nanodiamond-graphene support (denoted as Pd3/ND@G) for low-temperature dehydrogenation of ethylbenzene to styrene. The obtained fully exposed and atomically dispersed Pd clusters exhibit good catalytic performance (328 mmol gPd-1 h-1 ethylbenzene conversion rate and >99% styrene selectivity) and much enhanced stability under oxygen-free conditions at 350 °C, compared with the previously reported catalysts. The synergetic interaction between adjacent Pd atoms in each cluster evidenced by density functional theory (DFT) calculations guarantees effective activation of C-H bond on ethyl in ethylbenzene and easy desorption of styrene, which is the key for the higher activity than typical Pd single atom and Pd nanoparticle catalysts. The present method for precise control of fully exposed Pd clusters paves a new way for designing direct dehydrogenation catalyst at the atomic scale. © 2021 American Chemical Society.

Metal nanoparticle (NP), cluster and isolated metal atom (or single atom, SA) exhibit different catalytic performance in heterogeneous catalysis originating from their distinct nanostructures. To maximize atom efficiency and boost activity for catalysis, the construction of structure–performance relationship provides an effective way at the atomic level. Here, we successfully fabricate fully exposed Pt3 clusters on the defective nanodiamond@graphene (ND@G) by the assistance of atomically dispersed Sn promoters, and correlated the n-butane direct dehydrogenation (DDH) activity with the average coordination number (CN) of Pt-Pt bond in Pt NP, Pt3 cluster and Pt SA for fundamentally understanding structure (especially the sub-nano structure) effects on n-butane DDH reaction at the atomic level. The as-prepared fully exposed Pt3 cluster catalyst shows higher conversion (35.4%) and remarkable alkene selectivity (99.0%) for n-butane direct DDH reaction at 450 °C, compared to typical Pt NP and Pt SA catalysts supported on ND@G. Density functional theory calculation (DFT) reveal that the fully exposed Pt3 clusters possess favorable dehydrogenation activation barrier of n-butane and reasonable desorption barrier of butene in the DDH reaction. © 2021, The Author(s).

The product selectivity in catalytic hydrogenation of nitriles is strongly correlated with the structure of the catalyst. In this work, two types of atomically dispersed Pd species stabilized on the defect-rich nanodiamond-graphene (ND@G) hybrid support: single Pd atoms (Pd1/ND@G) and fully exposed Pd clusters with average three Pd atoms (Pdn/ND@G), were fabricated. The two catalysts show distinct difference in the catalytic transfer hydrogenation of nitriles. The Pd1/ND@G catalyst preferentially generates secondary amines (Turnover frequency (TOF@333 K 709 h−1, selectivity >98%), while the Pdn/ND@G catalyst exhibits high selectivity towards primary amines (TOF@313 K 543 h−1, selectivity >98%) under mild reaction conditions. Detailed characterizations and density functional theory (DFT) calculations show that the structure of atomically dispersed Pd catalysts governs the dissociative adsorption pattern of H2 and also the hydrogenation pathway of the benzylideneimine (BI) intermediate, resulting in different product selectivity over Pd1/ND@G and Pdn/ND@G, respectively. The structure-performance relationship established over atomically dispersed Pd catalysts provides valuable insights for designing catalysts with tunable selectivity. © 2021, The Author(s).

Direct dehydrogenation of alkanes is of great interest but presents a significant challenge in activating C-H bond at a low temperature. Here, we report fully exposed Pd clusters consisting of an average of three Pd atoms on a hybrid nanodiamond-graphene support (denoted as Pd3/ND@G) for low-temperature dehydrogenation of ethylbenzene to styrene. The obtained fully exposed and atomically dispersed Pd clusters exhibit good catalytic performance (328 mmol gPd-1 h-1 ethylbenzene conversion rate and >99% styrene selectivity) and much enhanced stability under oxygen-free conditions at 350 °C, compared with the previously reported catalysts. The synergetic interaction between adjacent Pd atoms in each cluster evidenced by density functional theory (DFT) calculations guarantees effective activation of C-H bond on ethyl in ethylbenzene and easy desorption of styrene, which is the key for the higher activity than typical Pd single atom and Pd nanoparticle catalysts. The present method for precise control of fully exposed Pd clusters paves a new way for designing direct dehydrogenation catalyst at the atomic scale. © 2021 American Chemical Society.

Metal nanoparticle (NP), cluster and isolated metal atom (or single atom, SA) exhibit different catalytic performance in heterogeneous catalysis originating from their distinct nanostructures. To maximize atom efficiency and boost activity for catalysis, the construction of structure–performance relationship provides an effective way at the atomic level. Here, we successfully fabricate fully exposed Pt3 clusters on the defective nanodiamond@graphene (ND@G) by the assistance of atomically dispersed Sn promoters, and correlated the n-butane direct dehydrogenation (DDH) activity with the average coordination number (CN) of Pt-Pt bond in Pt NP, Pt3 cluster and Pt SA for fundamentally understanding structure (especially the sub-nano structure) effects on n-butane DDH reaction at the atomic level. The as-prepared fully exposed Pt3 cluster catalyst shows higher conversion (35.4%) and remarkable alkene selectivity (99.0%) for n-butane direct DDH reaction at 450 °C, compared to typical Pt NP and Pt SA catalysts supported on ND@G. Density functional theory calculation (DFT) reveal that the fully exposed Pt3 clusters possess favorable dehydrogenation activation barrier of n-butane and reasonable desorption barrier of butene in the DDH reaction. © 2021, The Author(s).

Direct dehydrogenation of alkanes is of great interest but presents a significant challenge in activating C-H bond at a low temperature. Here, we report fully exposed Pd clusters consisting of an average of three Pd atoms on a hybrid nanodiamond-graphene support (denoted as Pd3/ND@G) for low-temperature dehydrogenation of ethylbenzene to styrene. The obtained fully exposed and atomically dispersed Pd clusters exhibit good catalytic performance (328 mmol gPd-1 h-1 ethylbenzene conversion rate and >99% styrene selectivity) and much enhanced stability under oxygen-free conditions at 350 °C, compared with the previously reported catalysts. The synergetic interaction between adjacent Pd atoms in each cluster evidenced by density functional theory (DFT) calculations guarantees effective activation of C-H bond on ethyl in ethylbenzene and easy desorption of styrene, which is the key for the higher activity than typical Pd single atom and Pd nanoparticle catalysts. The present method for precise control of fully exposed Pd clusters paves a new way for designing direct dehydrogenation catalyst at the atomic scale. © 2021 American Chemical Society.

Metal nanoparticle (NP), cluster and isolated metal atom (or single atom, SA) exhibit different catalytic performance in heterogeneous catalysis originating from their distinct nanostructures. To maximize atom efficiency and boost activity for catalysis, the construction of structure–performance relationship provides an effective way at the atomic level. Here, we successfully fabricate fully exposed Pt3 clusters on the defective nanodiamond@graphene (ND@G) by the assistance of atomically dispersed Sn promoters, and correlated the n-butane direct dehydrogenation (DDH) activity with the average coordination number (CN) of Pt-Pt bond in Pt NP, Pt3 cluster and Pt SA for fundamentally understanding structure (especially the sub-nano structure) effects on n-butane DDH reaction at the atomic level. The as-prepared fully exposed Pt3 cluster catalyst shows higher conversion (35.4%) and remarkable alkene selectivity (99.0%) for n-butane direct DDH reaction at 450 °C, compared to typical Pt NP and Pt SA catalysts supported on ND@G. Density functional theory calculation (DFT) reveal that the fully exposed Pt3 clusters possess favorable dehydrogenation activation barrier of n-butane and reasonable desorption barrier of butene in the DDH reaction. © 2021, The Author(s).

The product selectivity in catalytic hydrogenation of nitriles is strongly correlated with the structure of the catalyst. In this work, two types of atomically dispersed Pd species stabilized on the defect-rich nanodiamond-graphene (ND@G) hybrid support: single Pd atoms (Pd1/ND@G) and fully exposed Pd clusters with average three Pd atoms (Pdn/ND@G), were fabricated. The two catalysts show distinct difference in the catalytic transfer hydrogenation of nitriles. The Pd1/ND@G catalyst preferentially generates secondary amines (Turnover frequency (TOF@333 K 709 h−1, selectivity >98%), while the Pdn/ND@G catalyst exhibits high selectivity towards primary amines (TOF@313 K 543 h−1, selectivity >98%) under mild reaction conditions. Detailed characterizations and density functional theory (DFT) calculations show that the structure of atomically dispersed Pd catalysts governs the dissociative adsorption pattern of H2 and also the hydrogenation pathway of the benzylideneimine (BI) intermediate, resulting in different product selectivity over Pd1/ND@G and Pdn/ND@G, respectively. The structure-performance relationship established over atomically dispersed Pd catalysts provides valuable insights for designing catalysts with tunable selectivity. © 2021, The Author(s).

Atomically dispersed metal catalysts (ADMCs), which offer maximized atom-use efficiency and catalytic performance enhancements for many catalytic systems, have received increasing attention in the catalysis field. Additionally, ADMCs with well-defined architectures are promising for providing valuable information to derive structure-performance relationships. Here, we immobilized Cu1 on a defective nanodiamond-graphene (ND@G) and N-doped nanodiamond-graphene (ND@NG). By changing the coordination environments (Cu-C or Cu-N), the electronic state of Cu ADMCs can be tailored. The highly oxidized Cu atoms in Cu-N AMDCs present distinctively different acetylene hydrogenation activity compared to that in Cu-C AMDCs (i.e., with high conversion (100%), high selectivity (93%), and good stability (more than for 100 h)). Density functional theory and H2-D2 exchange experiments reveal that Cu-C bond anchoring favors H2 dissociative adsorption, which is a rate-limiting step. In addition, the facile desorption of the target product C2H4 over Cu-C ADMCs ensures the outstanding activity and selectivity of the catalyst. This work thus helps to bring perspectives for linking activity and structures of ADMCs and designing active ADMCs for hydrogenation applications. © 2021 American Chemical Society.

Atomically dispersed metal catalysts (ADMCs), which offer maximized atom-use efficiency and catalytic performance enhancements for many catalytic systems, have received increasing attention in the catalysis field. Additionally, ADMCs with well-defined architectures are promising for providing valuable information to derive structure-performance relationships. Here, we immobilized Cu1 on a defective nanodiamond-graphene (ND@G) and N-doped nanodiamond-graphene (ND@NG). By changing the coordination environments (Cu-C or Cu-N), the electronic state of Cu ADMCs can be tailored. The highly oxidized Cu atoms in Cu-N AMDCs present distinctively different acetylene hydrogenation activity compared to that in Cu-C AMDCs (i.e., with high conversion (100%), high selectivity (93%), and good stability (more than for 100 h)). Density functional theory and H2-D2 exchange experiments reveal that Cu-C bond anchoring favors H2 dissociative adsorption, which is a rate-limiting step. In addition, the facile desorption of the target product C2H4 over Cu-C ADMCs ensures the outstanding activity and selectivity of the catalyst. This work thus helps to bring perspectives for linking activity and structures of ADMCs and designing active ADMCs for hydrogenation applications. © 2021 American Chemical Society.

The design of cheap, non-toxic, and earth-abundant transition metal catalysts for selective hydrogenation of alkynes remains a challenge in both industry and academia. Here, we report a new atomically dispersed copper (Cu) catalyst supported on a defective nanodiamond-graphene (ND@G), which exhibits excellent catalytic performance for the selective conversion of acetylene to ethylene, i.e., with high conversion (95%), high selectivity (98%), and good stability (for more than 60 h). The unique structural feature of the Cu atoms anchored over graphene through Cu-C bonds ensures the effective activation of acetylene and easy desorption of ethylene, which is the key for the outstanding activity and selectivity of the catalyst. © 2019, The Author(s).

The design of cheap, non-toxic, and earth-abundant transition metal catalysts for selective hydrogenation of alkynes remains a challenge in both industry and academia. Here, we report a new atomically dispersed copper (Cu) catalyst supported on a defective nanodiamond-graphene (ND@G), which exhibits excellent catalytic performance for the selective conversion of acetylene to ethylene, i.e., with high conversion (95%), high selectivity (98%), and good stability (for more than 60 h). The unique structural feature of the Cu atoms anchored over graphene through Cu-C bonds ensures the effective activation of acetylene and easy desorption of ethylene, which is the key for the outstanding activity and selectivity of the catalyst. © 2019, The Author(s).