The crystalline phase plays a crucial, yet not well-understood, role in enhancing the oxygen evolution reaction (OER) performance of iron oxyhydroxide (FeOOH) materials. Herein, single-phase (α-, β-, and δ-) and mixed-phase (α/β-, α/δ-, and β/δ-) FeOOH nanostructures have been successfully synthesized through a controlled solvothermal route. Combined analyses of X-ray photoelectron spectroscopy and partial density of state calculation suggest that rich oxygen vacancies confined in the mixed-phase FeOOH samples (with optimized electronic structure) can effectively improve the OER activity. Notably, the mixed phase of β/δ-FeOOH displays an enhanced OER activity and stability in the alkaline media, with a very low overpotential of ∼180 mV vs a reversible hydrogen electrode at 10 mA cm–2. Understanding of the phase-induced activity may also pave a pathway for the design and synthesis of highly efficient electrocatalysts.

Graphene continues to attract tremendous interest, owing to its excellent optical and electronic properties. On the basis of its unique features, graphene has been employed in the ever-expanding research fields. Surface-enhanced Raman scattering (SERS) may be one of the significant applied fields where graphene can make a difference. Since its discovery, SERS technique has been capable of ultra sensitively detecting chemical and biological molecules at very low concentration, even at single molecule level, but some problems, such as irreproducible SERS signals, should be overcome before practical application on spectra analysis. Graphene can be a promising candidate to make up the deficiency of conventional metal SERS substrate. Furthermore, graphene, serving as the enhancement material, is usually deemed as a chemically inert substance to isolate the interactions between metal and probe molecules. While, irradiated by laser, structure changes of graphene under specific conditions and the contributions of its high electron mobility in plasmoninduced catalytic reactions are often ignored. In this review, we mainly focus on the state-of-the-art applications of graphene in the fields of SERS and laser-induced catalytic reactions. The advances of informative Raman spectra of graphene are firstly reviewed. Then, the graphene related SERS substrates, including graphene-enhanced Raman scattering (GERS) and graphene-mediated SERS (G-SERS), are summarized. We finally highlight the catalytic reactions occurring on graphene itself and molecules adsorbed onto graphene upon laser irradiation.In this review, we mainly focus on the state-of-the-art applications of graphene in the fields of Surfaceenhanced Raman scattering (SERS) and plasmon-induced catalytic reactions. The advances of informative Raman spectra of graphene are firstly reviewed. Then, the graphene related SERS substrates, including graphene-enhanced Raman scattering (GERS) and graphene-mediated SERS (G-SERS), are summarized. We finally highlight the catalytic reactions occurring on graphene itself and molecules adsorbed onto graphene upon laser irradiation.

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Hydrogen production through photocatalytic water splitting has attracted much attention because of its potential to solve the issues of environmental pollution and energy shortage. In this work, CdS/CuS/g-CN ternary heterostructures are fabricated by ion exchange between CdS and Cu and subsequent ultrasonication-assisted self-assembly of CdS/CuS and g-CN, which provide excellent visible-light photocatalytic activity for hydrogen evolution without any noble metal cocatalyst. With the presence of p-n junction, tuned band gap alignments, and higher charge carrier density in the CdS/CuS/g-CN ternary heterostructures that can effectively promote the spatial separation and prolong the lifetime of photogenerated electrons, a high hydrogen evolution rate of 3570 μmol g h, an apparent quantum yield of 4.4% at 420 nm, and remarkable recycling stability are achieved. We believe that the as-synthesized CdS/CuS/g-CN ternary heterostructures can be promising noble metal-free catalysts for enhanced hydrogen production from photocatalytic water splitting.