Synthesis And Photo-/Electro Catalytic Properties Of Metal Sulfide Nanocluster-based Hybrid Materials

The semiconducting compounds based on metal chalcogenide supertetrahedral nanoclusters have stimulated great interests in the field of photoelectricity,catalysis,energy,gas absorption due to their precise adjustable composition and structure.Over the past few decades,the researches on the supertetrahedral nanocluster-based metal sulfides were mainly focused on the following two aspects:1)To synthesize crystals with different topological structures or open framework by adjusting the connection modes of the nanoclusters,which are hopefully to display the promising application in gas absorption,or sensing;2)To build new type of nanoclusters with multimetallic components,which can be acted as the structure model for exploring the component-related photoluminescence and electroluminescence.These studies still remained in the nanocluster-based bulky crystals,and their performances come from the aggregated nanoclusters,instead of single nanoclusters.Understanding the photoelectric properties of nanoclusters on the atomic or nano scale,exploring the interaction between atoms in the nanocluster,and in-depth studying the intrinsic performance of single nanoclusters are significative and necessary.However,such research on this level is still vacant.Based on this,we propose our research plan:to use the discrete metal sulfide nanoclusters as precursors to construct a series of nanocluster-based hybrid materials,and to explore nanocluster-involved photocatalytic and electro catalytic properties.The main works are summarized as follows:?1?We purposely selected the microcrystal based on the isolated supertetrahedral metal sulfide nanoclusters as precursors,made them dispersed in some suitable solvent for obtaining monodisperse and nanocluster-aggregate nanoparticles,and studied the dispersion behaviors and stability of nanoclusters.?2?We loaded supertetrahedral metal sulfide nanoclusters?MSNCs,T4-MnGaSnS?with pre-confined and precisely-positioned multi-metal ions on the surface of NRGO,and successfully developed MSNC-based electrocatalysts containing the MSNC-aggregated NPs with ultra-small size?about 4 nm?.By adjusting the divalent metal ions in the nanocluster,we noticed that the hybrid electrocatalyst containing the Mn/Co/Zn-codoped nanoclusters achieves the best HER performance with a low over-potential of 176 mV at10 mA cm^-2.DFT calculations show that the active sites for HER are sulfide ions at edges of nanoclusters,where the adsorption free energies of hydrogen atoms(?G_H*)are near zero.Confining multi-metal ions into one nanocluster provides a feasible strategy to modify not only the?G_H*,but also the energy barriers for the dissociation of hydrogen atoms from H₂O on Ga sites.This research clearly demonstrated the synergistic effect of multi-metal ions on tuning HER activity of metal sulfide nanocluster.?3?A facile and general strategy was presented to create well-defined heterojunctions with ultra-small multimetallic sulfide nanoparticles uniformly coated on sliver nanowires through an etching growth by a various of metal sulfides nanoclusters.The usage of such nanoclusters also enables the convenient formation of the ultrathin interfacial Ag₂S layer via etching.The heterojunctions?denoted as MMSNPs/Ag₂S/Ag-NWs?benefit from adjustable multimetallic components and display tunable visible-light-driven photocatalytic performance owing to the synergistic effect of multimetallic components from MMSNPs and the high carrier mobility of Ag-NWs.And the T4-MnZn GaSn/Ag₂S/Ag-NWs heterojunctions exhibiting the best H₂ evolution rate at35.68?mol g^-1 h^-1.The synthetic strategy opens a new route to designing and fabricating various heterojunctions with multimetallic components,which could further expand their applications in catalysis,electronics,and photonics.?4?We selected T5-Cd InS as the metal ion source to develop a facile approach to prepare Cd/In-codoped TiO₂ nanochips with the capability of visible light absorption.Such bimetallic-doped TiO₂ was synthesized through a two-step process:Cd/In/S-TiO₂ gels were first synthesized by mixing the preformed T5-Cd InS supertetrahedral nanoclusters with a titanium source,and the subsequent pyrolytic process effectively converted the gels into Cd/In-TiO₂ nanochips with a thickness of?2.19 nm and a uniform diameter of?10.60 nm,which shown the best degradation rate of dye under visible light.Interestingly,the absorption band of Cd/In-TiO₂ nanochips was adjusted by pyrolysis temperature,which further regulated the photocatalytic efficiency of dye degradation under visible light.Current research demonstrates that doping TiO₂ by multimetallic sulfide nanoclusters opens up a new door to further enrich the dopants in TiO₂ and broaden their potential applications.