Research Article Issue
Asymmetrically coordinated single atom Cu catalyst with unsaturated C–Cu–N structure for CO2 reduction to CO
Nano Research 2024, 17 (5): 3911-3918
Published: 12 January 2024
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Single atom catalysts (SACs) play a crucial role in energy catalysis due to their distinct coordination environment and high atomic utilization efficiency. This study focuses on the synthesis of a monatomic Cu catalyst with Cu–N1C1 coordination anchored to N-doped Ti3C2Tx MXene (Cu SA@N-Ti3C2Tx) to achieve efficient reduction of CO2 to CO. Detailed characterization, including morphology and multispectral analysis, confirmed the uniform distribution of asymmetrically coordinated Cu atoms in unsaturated C–Cu–N bridge fragments on Ti3C2Tx. The Cu SA@N-Ti3C2Tx catalyst exhibited an excellent CO selectivity with Faraday efficiency of 97.4% at −0.58 V vs. reversible hydrogen electrode (RHE) and satisfactory durability. The in situ X-ray absorption fine structure (XAFS) results confirmed that the carbon dioxide reduction reaction (CO2RR) product distribution is mainly affected by potential-dependent valence change of Cu species. These findings highlight the extensive potential of tuning coordination structure of MXene-based single-atom catalysts for CO2 reduction reactions.

Review Article Issue
Atomic design of carbon-based dual-metal site catalysts for energy applications
Nano Research 2023, 16 (5): 6477-6506
Published: 28 March 2023
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Carbon-based dual-metal sites catalysts (DMSCs) have emerged as a new frontier in the field of sustainable energy due to their unique coordination environments, electronic structure, and the maximized atom utilization. The reasonable utilization of carbon-based DMSCs provides new possibilities to achieve the outstanding catalytic performance, remarkable selectivity, and recyclability in energy-related catalysis. Based on this, this review intends to summarize the recent breakthroughs in carbon-based DMSCs for the energy catalysis. Firstly, the definition and classifications of DMSCs are proposed, mainly dividing into three types (isolated dual-metal site pairs, binuclear homologous dual-metal sites pairs, and binuclear heterologous dual-metal sites pairs). Subsequently, we discuss the potential of DMSCs targeting on energy conversion reactions, such as electrocatalytic hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), CO2 reduction reaction (CO2RR), and N2 reduction reaction (NRR). Finally, we predict the remaining challenges and possible opportunities on the unique carbon-based DMSCs for energy applications in the future.

Research Article Issue
Coordinatively unsaturated single Co atoms immobilized on C2N for efficient oxygen reduction reaction
Nano Research 2023, 16 (2): 2294-2301
Published: 23 November 2022
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Developing cost-effective and high-efficiency oxygen reduction reaction (ORR) catalysts is imperative for promoting the substantial progress of fuel cells and metal-air batteries. The coordination and geometric engineering of single-atom catalysts (SACs) occurred the promising approach to overcome the thermodynamics and kinetics problems in high-efficiency electrocatalysis. Herein, we rationally constructed atomically dispersed Co atoms on porous N-enriched graphene material C2N (CoSA-C2N) for efficient oxygen reduction reaction (ORR). Systematic characterizations demonstrated the active sites for CoSA-C2N is as identified as coordinatively unsaturated Co-N2 moiety, which exhibits ORR intrinsic activity. Structurally, the porous N-enriched graphene framework in C2N could effectively increase the accessibility to the active sites and promote mass transfer rate, contributing to improved ORR kinetics. Consequently, CoSA-C2N exhibited superior ORR performance in both acidic and alkaline conditions as well as impressive long-term durability. The coordination and geometric engineering of SACs will provide a novel approach to advanced catalysts for energy related applications.

Research Article Issue
Carbon-supported high-entropy Co-Zn-Cd-Cu-Mn sulfide nanoarrays promise high-performance overall water splitting
Nano Research 2022, 15 (7): 6054-6061
Published: 20 April 2022
Abstract PDF (9.2 MB) Collect

Transition metal sulfides with homogeneous multi-metallic elements promise high catalytic performance for water electrolysis owing to the unique structure and highly tailorable electrochemical property. Most existing synthetic routes require high temperature to ensure the uniform mixing of various elements, making the synthesis highly challenging. Here, for the first-time novel carbon fiber supported high-entropy Co-Zn-Cd-Cu-Mn sulfide (CoZnCdCuMnS@CF) nanoarrays are fabricated by the mild cation exchange strategy. Benefiting from the synergistic effect among multiple metals and the strong interfacial bonding between high-entropy Co-Zn-Cd-Cu-Mn sulfide nanoarrays and the carbon fiber support, CoZnCdCuMnS@CF exhibits superior catalytic activity and stability toward overall water splitting in alkaline medium. Impressively, CoZnCdCuMnS@CF only needs low overpotentials of 173 and 220 mV to reach the current density of 10 mA•cm−2, with excellent durability for over 70 and 113 h for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) respectively. More importantly, the bifunctional electrode (CoZnCdCuMnS@CF||CoZnCdCuMnS@CF) for overall water splitting can deliver a small cell voltage of 1.63 V to afford 10 mA•cm−2 and exhibit outstanding stability of negligible decay after 73 h continuous operation. This work provides a viable synthesis route toward advanced high-entropy materials with great potential applications.

Research Article Issue
Interfacial engineering of 3D hollow CoSe2@ultrathin MoSe2 core@shell heterostructure for efficient pH-universal hydrogen evolution reaction
Nano Research 2022, 15 (4): 2895-2904
Published: 06 November 2021
Abstract PDF (9.6 MB) Collect

Rational design and construction of low-cost and highly efficient electrocatalysts for hydrogen evolution reaction (HER) is meaningful but challenging. Herein, a robust three dimensional (3D) hollow CoSe2@ultrathin MoSe2 core@shell heterostructure (CoSe2@MoSe2) is proposed as an efficient HER electrocatalyst through interfacial engineering. Benefitting from the abundant heterogeneous interfaces on CoSe2@MoSe2, the exposed edge active sites are maximized and the charge transfer at the hetero-interfaces is accelerated, thus facilitating the HER kinetics. It exhibits remarkable performance in pH-universal conditions. Notably, it only needs an overpotential (η10) of 108 mV to reach a current density of 10 mA·cm−2 in 1.0 M KOH, outperforming most of the reported transition metal selenides electrocatalysts. Density functional theory (DFT) calculations unveil that the heterointerfaces synergistically optimize the Gibbs free energies of H2O and H* during alkaline HER, accelerating the reaction kinetics. The present work may provide new construction guidance for rational design of high-efficient electrocatalysts.

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