Constructing abundant surface/interface structures has significant impacts on improving the performance of electrochemical CO2 reduction reaction (CO2RR) catalysts. For developing high-performance CO2RR catalysts, herein we report a 0D/2D heterojunction structure of SnO2 nanodots (∼2 nm) confined on graphitic carbon nitride (g-C3N4) nanosheets for promoting the conversion of CO2 to formate. Experimental and theoretical studies demonstrate that the abundant N-coordinating sites of g-C3N4 and highly distributed SnO2 nanodots synergistically lead to strong metal oxide–support interactions, and the substantial heterojunction interface in SnO2/g-C3N4 has induced efficient electron transfer from electron-rich g-C3N4 to SnO2 mainly through p–p orbital couplings. As a result, the SnO2/g-C3N4 heterojunction provides superior activity and stability for the conversion of CO2RR to formate, with a Faradic efficiency of 91.7% at −0.88 V vs RHE. Moreover, the proposed 0D/2D heterojunction strategy was extended to In2O3/g-C3N4, supplying a universal strategy to achieve efficient hybrid catalysts for CO2RR in the production of high-value chemicals.
The practical uses of lithium–sulfur batteries are greatly restricted by the sluggish reaction kinetics of lithium polysulfides (LiPSs), leading to low sulfur utilization and poor cyclic stability. Using the heterostructure catalysts is an effective way to solve the above problems, but how to further enhance the conversion efficiency and avoid the surface passivation by the insulative Li2S has not been well investigated. Herein, a heterostructure catalyst with rich heterointerfaces was prepared by modifying Mo2N microbelt with SnO2 nanodots. The formed rich interfaces with high accessibility act as the profitable nucleation sites guiding the Li2S 3D growth, which avoids the catalyst surface passivation and facilitates the LiPS conversion. The introduction of SnO2 nanodots also enhances the LiPS adsorption. Thus, the assembled battery with the above catalyst as the cathode additive shows a high capacity of 738.3 mAh g–1 after 550 cycles at 0.5 C with an ultralow capacity decay of 0.025% per cycle. Even with high sulfur loading of 9.0 mg cm–2, good cyclic stability is also achieved at 0.5 C with a low E/S ratio of 5 μL mgs–1. This work shows an effective way to enhance the LiPS conversion kinetics and guide Li2S deposition in Li–S batteries.
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