We summarized the progress in the synthesis, doping and modification strategies of GQDs and the development and application of GQDs in energy storage and conversion devices.

Palladium nanoparticles were uniformly anchored on nitrogen-doped carbon nanotubes with a three-dimensional network structure (denoted as Pd/3DNCNTs) through a facile, surfactant-free, and green approach with ethanol as the reducing agent. As a robust catalyst for the ethanol electrocatalytic oxidation reaction (EOR), Pd/3DNCNTs exhibit superior improved electrocatalytic activity, accelerated kinetics, and robust stability, mainly attributed to the unique architecture features of the 3DNCNTs. The results of this part of the work reveal that the Pd/3DNCNTs with an infusive electrochemical property for EOR are promising for direct ethanol fuel cells (DEFCs) and various other applications in electrochemistry. Additionally, the green approach probably provides some new ideas for the design of other new catalysts for fuel cells.

Self-powered devices have great potential in daily applications ranging from portable electronics to wearable body sensors, yet their working lifetime and performance are normally limited by the low energy density of the power unit as well as additional resistive losses induced by connections between electronic and power moieties. Herein, we report an effective programmable laser-assisted fabrication of facilely integrated microphotocapacitors (integrated devices of solar cells and microsupercapacitors, mPCs) exhibiting high output voltage and energy density (32.3 μWh cm −2 ). An mPC pack (8 mPCs in series within a size of 3 × 3 cm 2 ) delivers an excellent V oc of 7.3 V, and an output voltage of 90 V can be obtained with an array of 14 mPC packs when tested outdoors under solar illumination (63 mW cm −2 ), setting a new benchmark for integrated self-charging power packs. These devices have also shown good stability (stable operation over 2000 cycles, 2.1 × 10 4 s) and performance under low-or intermittent-intensity light illuminations, highlighting their abilities to work indoors or under cloudy weather.