REVIEWS 45 Nanogenerators for Self-Powered Gas Sensing Zhen Wen,Qingqing Shen, Xuhui Sun 47 Recent Advances of Graphitic Carbon Nitride-Based Structures and Applications in Catalyst, Sensing, Imaging, and LEDs Aiwu Wang, Chundong Wang, Li Fu, Winnie Wong-Ng,Yucheng ...