Hydrogen has been hailed as a clean and sustainable alternative to finite fossil fuels in many energy systems. Water splitting is an important method for hydrogen production in high purity and large quantities. To accelerate the hydrogen evolution reaction (HER) rate, it is highly necessary to develop high efficiency catalysts and to select a proper electrolyte. Herein, the performances of non-noble metal-based carbon composites under various pH values (acid, alkaline and neutral media) for HER in terms of catalyst synthesis, structure and molecular design are systematically discussed. A detailed analysis of the structure-activity-pH correlations in the HER process gives an insight on the origin of the pH-dependence for HER, and provide guidance for future HER mechanism studies on non-noble metal-based carbon composites. Furthermore, this Review gives a fresh impetus to rational design of high-performance noble-metal-free composites catalysts and guide researchers to employ the established electrocatalysts in proper water electrolysis technologies.

Non-Noble Metal-based Carbon Composites in Hydrogen Evolution Reaction: Fundamentals to Applications.

In this review, for a variety of metals and semiconductors, an attempt is made to generalize observations in the literature on the effect of process conditions applied during photodeposition on (i) particle size distributions, (ii) oxidation states of the metals obtained, and (iii) consequences for photocatalytic activities. Process parameters include presence or absence of (organic) sacrificial agents, applied pH, presence or absence of an air/inert atmosphere, metal precursor type and concentration, and temperature. Most intensively reviewed are studies concerning (i) TiO2; (ii) ZnO, focusing on Ag deposition; (iii) WO3, with a strong emphasis on the photodeposition of Pt; and (iv) CdS, again with a focus on deposition of Pt. Furthermore, a detailed overview is given of achievements in structure-directed photodeposition, which could ultimately be employed to obtain highly effective photocatalytic materials. Finally, we provide suggestions for improvements in description of the photodeposition methods applied when included in scientific papers.

Methods, Mechanism, and Applications of Photodeposition in Photocatalysis: A Review.

0D to 3D carbon-based networks combined with pseudocapacitive electrode material for high energy density supercapacitor: A review

Electrocatalysts for hydrogen evolution reaction

Strategies for developing transition metal phosphides as heterogeneous electrocatalysts for water splitting

Facile synthesis of polypyrrole nanowires for high-performance supercapacitor electrode materials

Micro-nanostructured mixed metal vanadates have recently garnered enormous attention owing to their remarkable performances in catalysis, energy storage and conversion. In this work, we report the synthesis of amorphous aluminum vanadate hierarchical microspheres via a simple hydrothermal approach with polyvinylpyrrolidone as a surface directing agent. Amorphous aluminum vanadate hierarchical microspheres are firstly described as a kind of electrode material for supercapacitors. The measured specific capacitance of the amorphous aluminum vanadate electrode is 497 F g−1 at 1 A g−1 with good stability and a retention capacity of 89% after 10 000 cycles. In addition, the fabricated asymmetric supercapacitor device delivered better performance with an extended operating voltage window of 1.5 V, excellent cycle stability (10 000 cycles, 85% capacitance retention), high energy density (37.2 W h kg−1 at 1124.4 W kg−1) and high power density (11 250 W kg−1 at 25 W h kg−1). This study essentially offers a new kind of vanadate as an electrochemical active material for the development of supercapacitors.

Facile synthesis of amorphous aluminum vanadate hierarchical microspheres for supercapacitors

A facile and green method for synthesis of reduced graphene oxide/Ag hybrids as efficient surface enhanced Raman scattering platforms.

The development of low-cost and high-performance non-precious metal electrocatalysts for the hydrogen evolution reaction (HER) is highly desirable for the wide range of applications of molecular hydrogen as a clean renewable energy source. Here phosphorus doped single wall carbon nanotubes loaded with nanoparticles of iron carbide and iron phosphide are synthesized cost-effectively and time-efficiently using a one-pot and one-step chemical vapor deposition method, and exhibit superb catalytic activity for the HER. The nanohybrid electrocatalyst produces a current density of 20 mA cm−2 at an overpotential of 157 mV in acid solution and 331 mV in basic solution. The Tafel slope is 60.8 mV dec−1 in acid solution and 87.6 mV dec−1 in basic solution. The catalyst can work stably in both acidic and basic solutions with 100% faradaic efficiency. The superb performance correlates with the doping of single wall carbon nanotubes with phosphorus, and the synergistic effect of iron phosphide and iron carbide.

Qingli Huang

Papers

Facile synthesis of polypyrrole nanowires for high-performance supercapacitor electrode materials

Facile synthesis of amorphous aluminum vanadate hierarchical microspheres for supercapacitors

A facile and green method for synthesis of reduced graphene oxide/Ag hybrids as efficient surface enhanced Raman scattering platforms.

Phosphorus doped single wall carbon nanotubes loaded with nanoparticles of iron phosphide and iron carbide for efficient hydrogen evolution

Rapid fabrication of silver nanoparticle-coated filter paper as SERS substrate for low-abundance molecules detection