In this paper, we developed a green and facile approach to the synthesis of chemically converted graphene nanosheets (GNS) based on reducing sugars, such as glucose, fructose and sucrose using exfoliated graphite oxide (GO) as precursor. The obtained GNS is characterized with atomic force microscopy, UV-visible absorption spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and so on. The merit of this method is that both the reducing agents themselves and the oxidized products are environmentally friendly. It should be noted that, besides the mild reduction capability to GO, the oxidized products of reducing sugars could also play an important role as a capping reagent in stabilizing as-prepared GNS simultaneously, which exhibited good stability in water. This approach can open up the new possibility for preparing GNS in large-scale production alternatively. Moreover, it is found that GNS-based materials could be of great value for applications in various fields, such as good electrocatalytic activity toward catecholamines (dopamine, epinephrine, and norepinephrine).

Recent years have witnessed a dramatic increase in the production of sustainable and renewable energy. However, the electrochemical performances of the various systems are limited, and there is an intensive search for highly efficient electrocatalysts by more rational control over the size, shape, composition, and structure. Of particular interest are the studies on single-atom catalysts (SACs), which have sparked new interests in electrocatalysis because of their high catalytic activity, stability, selectivity, and 100 % atom utilization. In this Review, we introduce innovative syntheses and characterization techniques for SACs, with a focus on their electrochemical applications in the oxygen reduction/evolution reaction, hydrogen evolution reaction, and hydrocarbon conversion reactions for fuel cells (electrooxidation of methanol, ethanol, and formic acid). The electrocatalytic performance is further considered at an atomic level and the underlying mechanisms are discussed. The ultimate goal is the tailoring of single atoms for electrochemical applications.

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The oxygen evolution reaction (OER) is a kinetically sluggish anodic reaction that requires rationalized compositions and structures for achieving highly efficient and reliable noble metal-based electrocatalysts in acidic electrolyte.