Tunable MoS2/SnO2 P-N Heterojunctions for an Efficient Trimethylamine Gas Sensor and 4-Nitrophenol Reduction Catalyst

Synthetic design and construction of P-N heterojunctions are attracting increasing attention due to their potential applications such as in catalysis, gas sensors, and energy storage and conversion. In general, the design strategies of P-N heterojunctions target one specific property. The construction of multifunctional materials with different functions remains an interesting and challenging research pursuit. Especially, multifunctional properties switched within a given chemical combination have rarely been found. Herein, by adjusting the mole ratio between MoS2 and SnO2, the first bifunctional MoS2/SnO2 P-N heterojunctions have been realized within a particular chemical system. As a result of the combination of MoS2 nanosheets and SnO2 nanofibers, MoS2/SnO2 heterojunctions exhibit great potential in both gas sensors and catalysts. With low loading of MoS2 (molar ratio, Mo/Sn = 0.53), the P-N heterojunction exhibits superior sensing selectivity and long-term stability toward trimethylamine. With increased MoS2 amount, the P-N heterojunctions display very good catalytic activities for 4-nitrophenol reduction. The bifunctional MoS2/SnO2 P-N heterojunctions with high sensitivity, selectivity, stability, and catalytic activity are promising candidates for practical applications. It can be anticipated that the synthetic strategy reported here will create new opportunities for realizing multifunctional materials by the rational design of P-N heterojunctions.