Over the past several decades, much effort has been applied to atmospheric nitrogen oxide (NOx) abatement. The current techniques require high energy consumption and result in secondary pollution. Particularly, the removal of low dose (<200 ppm) of NOx has been very challenging. Though graphitic carbon nitride (g‐CN), an eco‐friendly and sustainable material was tried as a promising metal‐free photocatalyst for NOx abatement. Herein, a one‐step, energy efficient calcination approach is developed to prepare amorphous carbon nitride (ACN) with N3C‐site vacancies. The visible‐light responsive range is expanded and the activation barrier of NO triple bonds is sharply decreased by one order of magnitude; 0.19 eV when compared to the 2.22 eV of g‐CN. These modifications allow the NOx removal efficiency of ACN to reach 57.1% which is among the highest in visible light. The unique N3C‐site vacancies are well maintained after photocatalytic NO oxidation, which shows an exceptional structural stability. This boosts the generation of singlet oxygen (1O2) and superoxide radical (•O2−) for complete NO removal. This study sheds light on the active site design and photocatalytic performance enhancement of g‐CN based materials by vacancy engineering.

Photocatalytic conversion of CO2 to high-value products plays a crucial role in the global pursuit of carbon–neutral economy. Junction photocatalysts, such as the isotype heterojunctions, offer an ideal paradigm to navigate the photocatalytic CO2 reduction reaction (CRR). Herein, we elucidate the behaviors of isotype heterojunctions toward photocatalytic CRR over a representative photocatalyst, g-C3N4. Impressively, the isotype heterojunctions possess a significantly higher efficiency for the spatial separation and transfer of photogenerated carriers than the single components. Along with the intrinsically outstanding stability, the isotype heterojunctions exhibit an exceptional and stable activity toward the CO2 photoreduction to CO. More importantly, by combining quantitative in situ technique with the first-principles modeling, we elucidate that the enhanced photoinduced charge dynamics promotes the production of key intermediates and thus the whole reaction kinetics.

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Piezo‐electrocatalysis as an emerging mechano‐to‐chemistry energy conversion technique opens multiple innovative opportunities and draws great interest over the past decade. However, the two potential mechanisms in piezo‐electrocatalysis, i.e., screening charge effect and energy band theory, generally coexist in the most piezoelectrics, making the essential mechanism remain controversial. Here, for the first time, the two mechanisms in piezo‐electrocatalytic CO2 reduction reaction (PECRR) is distinguished through a narrow‐bandgap piezo‐electrocatalyst strategy using MoS2 nanoflakes as demo. With conduction band of −0.12 eV, the MoS2 nanoflakes are unsatisfied for CO2‐to‐CO redox potential of −0.53 eV, yet they achieve an ultrahigh CO yield of ≈543.1 µmol g−1 h−1 in PECRR. Potential band position shifts under vibration are still unsatisfied with CO2‐to‐CO potential verified by theoretical investigation and piezo‐photocatalytic experiment, further indicating that the mechanism of piezo‐electrocatalysis is independent of band position. Besides, MoS2 nanoflakes exhibit unexpected intense “breathing” effect under vibration and enable the naked‐eye‐visible inhalation of CO2 gas, independently achieving the complete carbon cycle chain from CO2 capture to conversion. The CO2 inhalation and conversion processes in PECRR are revealed by a self‐designed in situ reaction cell. This work brings new insights into the essential mechanism and surface reaction evolution of piezo‐electrocatalysis.