Programming Bifunctional Metal-Organic Frameworks to Integrate Multiple Triboelectric Nanogenerators for Green...

Programming and synthesizing bifunctional materials for regulating the output of triboelectric nanogenerators (TENGs) and their photocatalytic efficiency is a promising strategy for energy harvesting to build self-powered systems. Herein, we tackle this challenge by introducing metal-organic frameworks (MOFs) as molecular catalysts and triboelectric layers for self-powered photocatalytic systems. A zeolite-like mixed-valence MOF (CuCu-1) and a ladder-structured MOF (Cu-2) were obtained through structural transformation. Due to the excellent charge-trapping capability and surface potential of CuCu-1, the outputs of CuCu-1-TENG (a short-circuit current (I_sc) of 30.4 μA and an open-circuit voltage (V_oc) of 524.1 V) were significantly superior to those of Cu-2-TENG. The incorporation of CuCu-1 with ethylcellulose (EC) to form CuCu-1@EC composite films greatly improved the TENG outputs, and the 10% CuCu-1@EC-TENG offered the maximum I_sc (57.2 μA) and V_oc (986.8 V). Furthermore, multiple 10% CuCu-1@EC-TENG devices were integrated in parallel to assemble multiple TENG devices (M-TENG) to harvest biomechanical energy, which displayed significant potential to continuously power blue LEDs, generating blue-light irradiation to trigger the photocatalytic C(sp)-H/Si-H cross-coupling reactions of aromatic alkyne and trimethylsilane for alkynylsilane over the photocatalysts CuCu-1 and Cu-2. The results revealed that CuCu-1 achieved a cooperative effect on remarkable catalytic selectivity and activity. This work demonstrates that bifunctional MOFs can serve as friction electrode materials for the large-scale integration and assembly of MOF-based TENG, and photocatalysts for achieving self-powered photocatalytic systems.