Photoreforming of lignocellulose is a promising approach toward sustainable H generation, but this kinetically challenging reaction currently requires UV-absorbing or toxic light absorbers under harsh conditions. Here, we report a cyanamide-functionalized carbon nitride, CN, which shows enhanced performance upon ultrasonication. This activated CN allows for the visible-light driven conversion of purified and raw lignocellulose samples into H in the presence of various proton reduction cocatalysts. The reported room-temperature photoreforming process operates under benign aqueous conditions (pH ≈ 2-15) without the need for toxic components.

The present study considers the ways in which redox enzyme modules are coupled in living cells for linking reductive and oxidative half-reactions, and then reviews examples in which this concept can be exploited technologically in applications of coupled enzyme pairs. We discuss many examples in which enzymes are interfaced with electronically conductive particles to build up heterogeneous catalytic systems in an approach which could be termed synthetic biochemistry. We focus on reactions involving the H+/H2 redox couple catalysed by NiFe hydrogenase moieties in conjunction with other biocatalysed reactions to assemble systems directed towards synthesis of specialised chemicals, chemical building blocks or bio-derived fuel molecules. We review our work in which this approach is applied in designing enzyme-modified particles for H2-driven recycling of the nicotinamide cofactor NADH to provide a clean cofactor source for applications of NADH-dependent enzymes in chemical synthesis, presenting a combination of published and new work on these systems. We also consider related photobiocatalytic approaches for light-driven production of chemicals or H2 as a fuel. We emphasise the techniques available for understanding detailed catalytic properties of the enzymes responsible for individual redox half-reactions, and the importance of a fundamental understanding of the enzyme characteristics in enabling effective applications of redox biocatalysis.

The conducting polymer polyaniline (PANI) has been considered to be a promising pseudocapacitive electrode material for supercapacitors due to its high specific capacitance, low cost, and environmental friendliness. However, the poor cycling stability of PANI during the charge–discharge processes limits its widespread practical application. Herein, a facile synthetic method is demonstrated for covalently grafting an aniline tetramer (TANI), the basic building block of PANI, onto 3D graphene networks via perfluorophenylazide coupling chemistry to create a hybrid electrode material for ultralong‐life supercapacitors. The design, which substitutes long‐chain PANI with short‐chain TANI and introduces covalent linkages between TANI and 3D graphene, greatly enhances the charge–discharge cycling stability of PANI‐based supercapacitors. The electrode material, as well as the fabricated symmetric all‐solid‐state supercapacitors, exhibit extraordinary long cycle life (>85% capacitance retention after 30 000 charge–discharge cycles). The capacitance can be further boosted through fast and reversible redox reactions on the electrode surface using a redox‐active electrolyte while maintaining outstanding cycling stability (82% capacitance retention after 100 000 cycles for a symmetric all‐solid‐state device). While conducting polymers are known to be limited by their poor cycling stability, this work provides an effective strategy to achieve enhanced cycle life for conducting polymer‐based energy storage devices.

Supercapacitors have emerged as one of the leading energy‐storage technologies due to their short charge/discharge time and exceptional cycling stability; however, the state‐of‐the‐art energy density is relatively low. Hybrid electrodes based on transition metal oxides and carbon‐based materials are considered to be promising candidates to overcome this limitation. Herein, a rational design of graphene/VOx electrodes is proposed that incorporates vanadium oxides with multiple oxidation states onto highly conductive graphene scaffolds synthesized via a facile laser‐scribing process. The graphene/VOx electrodes exhibit a large potential window with a high three‐electrode specific capacitance of 1110 F g–1. The aqueous graphene/VOx symmetric supercapacitors (SSCs) can reach a high energy density of 54 Wh kg–1 with virtually no capacitance loss after 20 000 cycles. Moreover, the flexible quasi‐solid‐state graphene/VOx SSCs can reach a very high energy density of 72 Wh kg–1, or 7.7 mWh cm–3, outperforming many commercial devices. With Rct < 0.02 Ω and Coulombic efficiency close to 100%, these gel graphene/VOx SSCs can retain 92% of their capacitance after 20 000 cycles. The process enables the direct fabrication of redox‐active electrodes that can be integrated with essentially any substrate including silicon wafers and flexible substrates, showing great promise for next‐generation large‐area flexible displays and wearable electronic devices.