Rongchao Jin

High cost and depletion of fossil fuels obligate the researchers to find energy sources that are not only renewable but can also replace the conventional sources. In this work, various catalysts namely, CdS, Cu@CdS, Ni@CdS and Cu/Ni@CdS were synthesized by the hydrothermal technique. To enhance the activity and stability, Cu/Ni cocatalysts were in-situ deposited over CdS surfaces by chemical reduction method. As-prepared catalysts were employed for photoreaction to generate hydrogen from water-splitting. The optical characteristics of catalysts were determined by UV-VIS/DRS and PL techniques. Morphology of catalysts was evaluated by XRD, Raman, SEM and AFM analysis. The surface properties and elemental compositions were justified via EDX and XPS analysis. Comparative H2 generation activities were monitored at GC-TCD (Shimadzu-2010). Results depict that an optimized ratio of cocatalysts (i …

Atomically precise control over anisotropic nanoclusters constitutes a grand challenge in nanoscience. In this work, we report our success in achieving a periodic series of atomically precise gold quantum rods (abbrev. Au QRs) with unusual excitonic properties. These QRs possess hexagonal close-packed kernels with a constant three-atom diameter but increasing aspect ratios (ARs) from 6.3 to 18.7, all being protected by the same thiolate (SR) ligand. The kernels of the QRs are in a Au1–(Au3)n–Au1 configuration (where n is the number of Au3 layers) and follow a periodic elongation with a uniform Au18(SR)12 increment consisting of four Au3 layers. These Au QRs possess distinct HOMO–LUMO gaps (Eg = 0.6 to 1.3 eV) and exhibit strongly polarized excitonic transition along the longitudinal direction, resulting in very intense absorption in the near-infrared (800 to 1,700 nm). While excitons in gapped systems …

The synthesis of atomically precise gold nanoclusters with high photoluminescence quantum yield (PLQY) in the near-infrared (NIR) region and understanding their photoluminescence mechanism are crucial for both fundamental science and practical applications. Herein, we report a highly luminescent, molecularly pure Au39(PET)29 (PET = 2-phenylethanethiolate) nanocluster with PLQY of 19% in the NIR range (915 nm). Steady state and time-resolved PL analyses, as well as temperature-dependent PL measurements reveal the emission nature of Au39(PET)29, which consists of prompt fluorescence (weak), thermally activated delayed fluorescence (TADF), and phosphorescence (predominant). Furthermore, strong dipole–dipole interaction in the solid-state (e.g., Au39(PET)29 nanoclusters embedded in a polystyrene thin-film) is found to narrow the energy gap between the S1 and T1 states, which results in …

Assembly of nanoparticles (NPs) is of crucial importance for the construction of functional materials and devices. Although tremendous progress has been made in constructing various types of superlattices, it is still difficult to elucidate the assembly mechanism at the molecular/atomic level, because the surface ligands and interactions cannot be seen by electron microscopy. To tackle this, we adopt an atomically precise nanochemistry approach and demonstrate with oblate [Au31Cu32(SPhtBu)34(P(SC4H3)3)8]+ nanoclusters (NCs) which can self-assemble into both template-free spherical superstructures upon fast evaporation and single crystals via slow non-solvent diffusion. The size of the assembled solid nanospheres (∼300 nm) can be controlled by the amount of n-hexane (non-solvent) added to the Au31Cu32 solution. On the other hand, adding a second solvent of lower vapor pressure leads to hollow …

The risk of global warming is increased due to increasing the demands of energy. To fill the gap between production and consumption of conventional energy sources (fossil fuel), modern societies are searching green and renewable alternatives. In this work, BiVO4/Zn3V2O8 heterocatalysts were synthesized and interfacially engineered for overall water splitting reactions. To obtain structural and interfacial morphologies, catalysts were characterized by XRD, FTIR, Raman spectroscopy, SEM and AFM techniques. The optical and chemical characteristics of as-synthesized catalysts were evaluated using UV–Vis/DRS, PL, EIS, EDX, XPS and BET analysis. The role of Cu metal, synergism between BiVO4/Zn3V2O8 and mechanistic approaches were further revealed. The results depict that Cu metal exceptionally compete to sustain the synergism as an electron mediator source. The synergistic effect and electron …

An Au36(S-tBu)22 nanocluster (NC) is synthesized using the bulky tert-butyl thiol as the ligand. Single-crystal X-ray crystallography reveals that it has an Au25 core which evolves from the Au22 core in the previously reported Au30(S-tBu)18, and the Au25 core is protected by longer staple-like surface motifs. The new Au36 NC extends the members of the face-centered cubic structural evolution by adding an Au3 triangle and an Au4 tetrahedron unit. Additionally, it is found that Au36 emits near-infrared photoluminescence at 863 nm with a quantum yield (QY) of 4.3%, which is five times larger than that of Au30(S-tBu)18─the closest neighbor in the structural evolution pattern. The higher QY of Au36 is attributed to a larger radiative relaxation (kr), resulting from the structural effect. Finally, we find that the longer staple motifs lead to enhanced stability of Au36(S-tBu)22 relative to Au30(S-tBu)18.

Increasing energy demands and environmental problems require carbon-free and renewable energy generation systems. For this purpose, we have synthesized efficient photocatalysts (i.e., g-C3N4, Cu@g-C3N4, Ce@g-C3N4 and Cu/Ce@g-C3N4) for H2 evolution from water splitting. Their optical, structural and electrochemical properties were investigated by UV-Vis-DRS, PL, XRD, FTIR, Raman and EIS methods. Their surface morphologies were evaluated by AFM and SEM analyses. Their chemical characteristics, compositions and stability were assessed using XPS, EDX and TGA techniques. Photoreactions were performed in a quartz reactor (150 mL/Velp-UK), whereas hydrogen generation activities were monitored using a GC-TCD (Shimadzu-2014/Japan). The results depicted that Cu/Ce@g-C3N4 catalysts are the most active catalysts that deliver 23.94 mmol g−1 h−1 of H2. The higher rate of H2 evolution …

Ultrasmall metal nanoclusters (NCs) exhibit a quantized conduction band, hence, a distinct HOMO‐LUMO gap (Eg). Such a quantized electronic structure gives rise to multiple discrete peaks in the optical absorption spectrum of the NCs. As the size grows to 130 gold atoms (Au130 protected by ligands), electrical charging and optical behaviors seem to show certain metal‐like features (hence, transition‐sizes). To probe such behaviors, especially the potential ligand effect, we have devised the synthesis of Au130 NCs protected by phenylethanethiolate and naphthalenethiolate, respectively, with the former having a nonconjugated separation between the aromatic molecular group and the metal core while the latter being in direct bonding. A careful comparison of these two Au130 nanoclusters with the earlier reported analogues is carried out, including the structurally characterized Au130(pMBT)50 and the aqueous …