Research Article Issue
Rationally construction of atomic-precise interfacial charge transfer channel and strong build-in electric field in nanocluster-based Z-scheme heterojunctions with enhanced photocatalytic hydrogen production
Nano Research 2024, 17 (6): 5002-5010
Published: 29 February 2024

The lack of effective charge transfer driving force and channel limits the electron directional migration in nanoclusters (NC)-based heterostructures, resulting in poor photocatalytic performance. Herein, a Z-scheme NC-based heterojunction (Pt1Ag28-BTT/CoP, BTT = 1,3,5-benzenetrithiol) with strong internal electric field is constructed via interfacial Co–S bond, which exhibits an absolutely superiority in photocatalytic performance with 24.89 mmol·h−1·g−1 H2 production rate, 25.77% apparent quantum yield at 420 nm, and ~ 100% activity retention in stability, compared with Pt1Ag28-BDT/CoP (BDT = 1,3-benzenedithiol), Ag29-BDT/CoP, and CoP. The enhanced catalytic performance is contributed by the dual modulation strategy of inner core and outer shell of NC, wherein, the center Pt single atom doping regulates the band structure of NC to match well with CoP, builds internal electric field, and then drives photogenerated electrons steering; the accurate surface S modification promotes the formation of Co–S atomic-precise interface channel for further high-efficient Z-scheme charge directional migration. This work opens a new avenue for designing NC-based heterojunction with matchable band structure and valid interfacial charge transfer.

Research Article Issue
Design of bifunctional single-atom catalysts NiSA/ZIF-300 for CO2 conversion by ligand regulation strategy
Nano Research 2024, 17 (5): 3827-3834
Published: 12 December 2023

Carbon-supported noble-metal-free single-atom catalysts (SACs) have aroused widespread interest due to their green chemistry aspects and excellent performances. Herein, we propose a “ligand regulation strategy” and achieve the successful fabrication of bifunctional SAC/MOF (MOF = metal–organic framework) nanocomposite (abbreviated NiSA/ZIF-300; ZIF = ZIF-8) with exceptional catalytic performance and robustness. The designed NiSA/ZIF-300 has a planar interfacial structure with the Ni atom, involving one S and three N atoms bonded to Ni(II), fabricated by controllable pyrolysis of volatile Ni-S fragments. For CO2 cycloaddition to styrene epoxide, NiSA/ZIF-300 exhibits ultrahigh activity (turnover number (TON) = 1.18 × 105; turnover frequency (TOF) = 9830 molSC·molNi−1·h−1; SC = styrene carbonate) and durability at 70 °C under 1 atm CO2 pressure, which is much superior to Ni complex/ZIF, NiNP/ZIF-300, and most reported catalysts. This study offers a simple method of bifunctional SAC/MOF nanocomposite fabrication and usage, and provides guidance for the precise design of additional original SACs with unique catalytic properties.

Open Access Research Article Issue
Ligand-correlated crystalline assembly of nanoclusters with atomic precision
Polyoxometalates 2023, 2 (4): 9140035
Published: 22 September 2023

Understanding the assembly pattern of metal nanoclusters in crystalline units at the atomic level is crucial for an in-depth understanding of their supramolecular interactions and structure–property correlations. In this study, two Au9Ag6 nanoclusters bearing a similar framework were controllably synthesized and structurally determined. By tailoring the peripheral thiol ligands from SPhpOMe to SPhoMe (HSPhpOMe = 4-methoxythiophenol, HSPhoMe = 2-methylbenzenethiol), the hierarchical assembly of cluster molecules in their superlattice varied from “ABAB” to “ABCDABCD”. Based on the atomically precise structures of the two nanoclusters, we proposed that such differences in crystalline packing modes resulted from a combination of their structural differences, including intramolecular coordination preferences (Au–P vs. Ag–Cl), steric hindrance effects of thiol ligands (SPhpOMe vs. SPhoMe), and intra-/inter-cluster interactions (C–H···π, π···π, and H···H). We also investigated the structure/assembly-dependent optical properties of the two clusters at different states and rationalized the obtained structure–property correlations at the atomic level. Moreover, this study presented an interesting case for analyzing the hierarchical assembly of metal nanoclusters, allowing an in-depth understanding of the ligand effect on the crystalline assemblies of metal nanoclusters with atomic precision.

Research Article Issue
Atomically precise coreless AuCu bimetallic nanoclusters for Ullmann C–O coupling
Nano Research 2023, 16 (8): 10756-10762
Published: 15 June 2023

Bimetallic nanocluster with atomic precision has gained widespread attention due to its unique synergism. The coreless Au4Cu5 bimetallic nanoclusters were selected as models to explore the relationship between their microstructure and performance, and compare with the coreless monometallic nanoclusters, core–shell nanoclusters, and single atom catalyst (SAC). The experimental results show that the coreless bimetallic nanocluster catalyst Au4Cu5/activated carbon (AC) exhibits high activity and stability in the Ullmann C–O coupling reaction, much higher than coreless monometallic nanoclusters (Au11/AC and Cu11/AC), core–shell nanoclusters (Au25/AC, Cu25/AC, and Au1Cu24/AC), and single atom catalysts (Au SAC and Cu SAC). Moreover, the coreless Au4Cu5/AC catalyst efficiently catalyzed the Ullmann C–O coupling of benzyl alcohol for the first time. This structure–activity relationship was successfully extended to other coreless bimetallic systems, such as Au4Cu4/AC nanocluster, and it is expected to provide new insights for the design of bimetallic catalysts with well-defined performance.

Research Article Issue
Nicotinamide adenine dinucleotide (NAD+) reduction enabled by an atomically precise Au-Ag alloy nanocluster
Nano Research 2023, 16 (5): 7770-7776
Published: 16 February 2023

The redox property of the ultrasmall coinage nanoclusters (with several to tens of Au/Ag atoms) has elucidated the electron-transfer capacity of nanoclusters, and has been successfully utilized in a variety of redox conversions (such as from CO2 to CO). Nevertheless, their biological applications are mainly restricted by the scarcity of atomically precise, water-soluble metal nanoclusters, and the limited application (mainly on the decomposition of H2O2 in these days). Herein, mercaptosuccinic acid (MSA) protected ultrasmall alloy AuAg nanoclusters were prepared, and the main product was determined [Au3Ag5(MSA)3] by electrospray ionization mass spectrometry (ESI-MS). The clusters can not only mediate the decomposition of H2O2 to generate hydroxyl radicals, but is also able to mediate the reduction of nicotinamide adenine dinucleotide (NAD) to its reduced form of NADH. This is the first time that the atomically precise metal nanoclusters were used to mediate the coenzyme reduction. The preliminary mechanistic insights imply the reaction to be driven by the hydrogen bonding between the carboxylic groups (on the surface of MSA) and the amino N–H bonds (on NAD). In this context, the presence of the carboxylic groups, the sub-nanometer size regime (~ 1 nm), and the synergistic effect of the Au-Ag clusters are pre-requisite to the NAD reduction.

Research Article Issue
Covalence bridge atomically precise metal nanocluster and metal-organic frameworks for enhanced photostability and photocatalysis
Nano Research 2023, 16 (1): 1527-1532
Published: 10 August 2022

Metal nanoclusters (NCs) with precise structure and ultrasmall size have attracted great interests in catalysis. However, the poor stability has limited its large-scale use. Herein, we proposed the “covalence bridge” strategy to effectively connect atomically precise metal NCs and metal-organic frameworks. Benefiting from the covalent linkage, the synthesized UiO-66-NH2-Au25(L-Cys)18 showed outstanding stability after 16 h photocatalysis. Moreover, the covalence bridge created a strong metal-support interaction between the two components and provided an effective charge transport channel and thereby enhanced photocatalytic activity. UiO-66-NH2-Au25(L-Cys)18 displayed an exceptional photocatalytic H2 production rate, which is 21 and 90 times higher than that of UiO-66-NH2/Au25(PET)18 (made by physically combination) and bare UiO-66-NH2, respectively. Thermodynamic and kinetic studies demonstrated that UiO-66-NH2-Au25(L-Cys)18 exhibited higher charge transfer efficiency, lower overpotential of water reduction and activation energy barrier compared with its counterparts.

Research Article Issue
Exposing Cu-rich {110} active facets in PtCu nanostars for boosting electrochemical performance toward multiple liquid fuels electrooxidation
Nano Research 2019, 12 (5): 1147-1153
Published: 21 March 2019

In catalysis, tuning the structural composition of the metal alloy is known as an efficient way to optimize the catalytic activity. This work presents the synthesis of compositional segregated six-armed PtCu nanostars via a facile solvothermal method and their distinct composition-structure-dependent performances in electrooxidation processes. The alloy is shown to have a unique six arms with a Cu-rich dodecahedral core, mainly composed of {110} facets and exhibit superior catalytic activity toward alcohols electrooxidation compared to the hollow counterpart where Cu was selectively etched. Density functional theory (DFT) calculations suggest that the formation of hydroxyl intermediate (OH*) is crucial to detoxify CO poisoning during the electrooxidation processes. The addition of Cu is found to effectively adjust the d band location of the alloy catalyst and thus enhance the formation of *OH intermediate from water splitting, which decreases the coverage of *CO intermediate. Our work demonstrates that the unique compositional anisotropy in alloy catalyst may boost their applications in electrocatalysis and provides a methodology for the design of this type catalyst.

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