Programming Bifunctional Metal–Organic Frameworks to Integrate Multiple Triboelectric Nanogenerators for Green Electronics toward Effective Self-Powered Photocatalytic System

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 (<b>Cu</b>^<b>I</b><b>Cu</b>^<b>II</b><b>-1</b>) and a ladder-structured MOF (<b>Cu</b>^<b>II</b><b>-2</b>) were obtained through structural transformation. Due to the excellent charge-trapping capability and surface potential of <b>Cu</b>^<b>I</b><b>Cu</b>^<b>II</b><b>-1</b>, the outputs of <b>Cu</b>^<b>I</b><b>Cu</b>^<b>II</b><b>-1-TENG</b> (a short-circuit current (<i>I</i>_sc) of 30.4 μA and an open-circuit voltage (<i>V</i>_oc) of 524.1 V) were significantly superior to those of <b>Cu</b>^<b>II</b><b>-2-TENG</b>. The incorporation of <b>Cu</b>^<b>I</b><b>Cu</b>^<b>II</b><b>-1</b> with ethylcellulose (EC) to form <b>Cu</b>^<b>I</b><b>Cu</b>^<b>II</b><b>-1@EC</b> composite films greatly improved the TENG outputs, and the 10% <b>Cu</b>^<b>I</b><b>Cu</b>^<b>II</b><b>-1@EC-TENG</b> offered the maximum <i>I</i>_sc (57.2 μA) and <i>V</i>_oc (986.8 V). Furthermore, multiple 10% <b>Cu</b>^<b>I</b><b>Cu</b>^<b>II</b><b>-1@EC-TENG</b> devices were integrated in parallel to assemble multiple TENG devices (<b>M-TENG</b>) 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 <b>Cu</b>^<b>I</b><b>Cu</b>^<b>II</b><b>-1</b> and <b>Cu</b>^<b>II</b><b>-2</b>. The results revealed that <b>Cu</b>^<b>I</b><b>Cu</b>^<b>II</b><b>-1</b> 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.