Kaiqin Xu,Shangbo Ning,Huayu Chen,Shuxin Ouyang,Jianbo Wang,Lizhu Song,Jun Lv,Jinhua Ye
A plum pudding-like Sn-based electrocatalyst is synthesized by calcinating the precursor SnC 2 O 4 on carbon black (CB) with polymeric carbon nitride (CN). This material exhibits a structure of a Sn metallic ball coated with a nitrogen-doped SnO x native layer (N-doped SnO x @Sn) embedded on a carbon matrix. The carbon matrix originates from the CB and the polymeric CN decomposition promotes electrical conductivity, leading to high electrochemical activity of the CN–Sn catalyst. The introduction of nitrogen that occupies the interstitial space of the surface SnO x layer further enhances electron transport; furthermore, it provides an electron-rich environment for oxygen because of its lower electronegativity, which is the fundamental cause of selectivity in the electrochemical reduction of CO 2 to CO. The maximum CO Faradaic efficiency over the optimal catalyst reaches 57.5%, with a high CO partial current density of 6.09 mA cm −2 at −0.7 V versus reversible hydrogen electrode. This catalyst is further applied to construct a photovoltaic–electrocatalytic CO 2 reduction/oxygen evolution reaction device to stably convert CO 2 to chemicals over 6 h at a high solar-to-fuel efficiency of 11.3%. This work explores a strategy of rational modulation on surface electronic structure to obtain high-performance electrocatalysts, inspiring the selectivity tuning in electrochemical CO 2 reduction via electronegativity difference of various elements.
The interface between the perovskite and electron-transporting material is often treated for defect passivation to improve the photovoltaic performance of devices. A facile 4-Acetamidobenzoic acid (containing an acetamido, a carboxyl, and a benzene ring)-based molecular synergistic passivation (MSP) strategy is developed here to engineer the SnO x /perovskite interface, in which dense SnO x are prepared using an E-beam evaporation technology while the perovskite is deposited with vacuum flash evaporation deposition method. MSP engineering can synergistically passivate defects at the SnO x /perovskite interface by coordinating with Sn 4+ and Pb 2+ with functional group CO in the acetamido and carboxyl. The optimized solar cell devices can achieve the highest efficiency of 22.51% based on E-Beam deposited SnO x and 23.29% based on solution-processed SnO 2 , respectively, accompanied by excellent stability exceeding 3000 h. Further, the self-powered photodetectors exhibit a remarkably low dark current of 5.22 × 10 −9 A cm −2 , a response of 0.53 A W −1 at zero bias, a detection limit of 1.3 × 10 13 Jones, and a linear dynamic range up to 80.4 dB. This work proposes a molecular synergistic passivation strategy to enhance the efficiency and responsivity of solar cells and self-powered photodetectors.
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