Liu Zhou

Bio: Liu Zhou is an academic researcher from Anhui University of Technology. The author has contributed to research in topics: Hydrogen production & Catalysis. The author has an hindex of 4, co-authored 6 publications receiving 67 citations.

Recent Advances in Noble Metal Catalysts for Hydrogen Production from Ammonia Borane

Abstract: Interest in chemical hydrogen storage has increased, because the supply of fossil fuels are limited and the harmful effects of burning fossil fuels on the environment have become a focus of public concern. Hydrogen, as one of the energy carriers, is useful for the sustainable development. However, it is widely known that controlled storage and release of hydrogen are the biggest barriers in large-scale application of hydrogen energy. Ammonia borane (NH3BH3, AB) is deemed as one of the most promising hydrogen storage candidates on account of its high hydrogen to mass ratio and environmental benignity. Development of efficient catalysts to further improve the properties of chemical kinetics in the dehydrogenation of AB under appropriate conditions is of importance for the practical application of this system. In previous studies, a variety of noble metal catalysts and their supported metal catalysts (Pt, Pd, Au, Rh, etc.) have presented great properties in decomposing the chemical hydride to generate hydrogen, thus, promoting their application in dehydrogenation of AB is urgent. We analyzed the hydrolysis of AB from the mechanism of hydrogen release reaction to understand more deeply. Based on these characteristics, we aimed to summarize recent advances in the development of noble metal catalysts, which had excellent activity and stability for AB dehydrogenation, with prospect towards realization of efficient noble metal catalysts.

Recent Developments of Effective Catalysts for Hydrogen Storage Technology Using N-Ethylcarbazole

Abstract: Hydrogen energy is considered to be a desired energy storage carrier because of its high-energy density, extensive sources, and is environmentally friendly. The development of hydrogen storage material, especially liquid organic hydrogen carrier (LOHC), has drawn intensive attention to address the problem of hydrogen utilization. Hydrogen carrier is a material that can reversibly absorb and release hydrogen using catalysts at elevated temperature, in which LOHC mainly relies on the covalent bonding of hydrogen during storage to facilitate long-distance transportation and treatment. In this review, the chemical properties and state-of-the-art of LOHCs were investigated and discussed. It reviews the latest research progress with regard to liquid organic hydrogen storage materials, namely N-ethylcarbazole, and the recent progress in the preparation of efficient catalysts for N-ethylcarbazole dehydrogenation by using metal multiphase catalysts supported by carbon–nitrogen materials is expounded. Several approaches have been considered to obtain efficient catalysts such as increasing the surface area of the support, optimizing particle size, and enhancing the porous structure of the support. This review provides a new direction for the research of hydrogen storage materials and considerations for follow-up research.

Pt-Ni Nanoalloys for H2 Generation from Hydrous Hydrazine

Abstract: Hydrous hydrazine (N2H4∙H2O) is a candidate for a hydrogen carrier for storage and transportation due to low material cost, high hydrogen content of 8.0%, and liquid stability at room temperature. Pt and Pt nanoalloy catalysts have been welcomed by researchers for the dehydrogenation of hydrous hydrazine recently. Therefore, in this review, we give a summary of Pt nanoalloy catalysts for the dehydrogenation of hydrous hydrazine and briefly introduce the decomposition mechanism of hydrous hydrazine to prove the design principle of the catalyst. The chemical characteristics of hydrous hydrazine and the mechanism of dehydrogenation reaction are briefly introduced. The catalytic activity of hydrous hydrazine on different supports and the factors affecting the selectivity of hydrogen catalyzed by Ni-Pt are analyzed. It is expected to provide a new way for the development of high-activity catalysts for the dehydrogenation of hydrous hydrazine to produce hydrogen.

A study on hydrogen, the clean energy of the future: Hydrogen storage methods

Abstract: Our need for energy is constantly increasing. We consume existing oil, coal and natural gas resources in order to obtain energy. As fossil fuels are exhausted, their prices have increased and new energy sources have been sought. It is possible to meet the daily energy demand with renewable energy sources. The utilization rates of renewable energy resources are gradually increasing. The use of fossil fuels is reduced in order to reduce carbon emissions in accordance with international agreements. Therefore, the use of clean energy resources is encouraged. In this article, hydrogen energy, which is a clean energy source, has been examined. Subjects such as hydrogen sources, production, storage and transportation have been investigated from articles in the literature. The current uses of hydrogen energy, limitations in hydrogen use, future uses, future goals have been examined. In this article, studies on hydrogen energy have been gathered together and it is aimed to create a source for future articles.

CuO and ZnO co-anchored on g-C3N4 nanosheets as an affordable double Z-scheme nanocomposite for photocatalytic decontamination of amoxicillin

Abstract: In this study, both CuO nanoparticles and ZnO nanorods were anchored on thermally-exfoliated g-C3N4 nanosheets (denoted as CZ@T-GCN) via isoelectric point-mediated annealing process as a novel nano-photocatalyst towards degradation of amoxicillin (AMOX). The features of prepared materials were characterized using BET, UV–vis DRS, XRD, FT-IR, XPS, FE-SEM, TEM, EIS and transient photocurrent techniques. These analyses demonstrated the successful formation of heterojunctions between components of CZ@T-GCN nanocomposite, which reflected in significantly increased electron-hole separation and enhanced degradation of AMOX as compared with pure substances. The investigation of influential operative parameters confirmed that the complete removal of AMOX could be attained under catalytic dosage of 0.9 g L−1 and pH of 7.0 within 120 min simulated sunlight illumination. Generation of OH upon illumination of catalysts was verified by terephthalic acid photoluminescence (TPA-PL) spectroscopy. Also, trapping tests proved that OH and O2 − were the major reactive radicals in AMOX decontamination. A novel double Z-scheme mechanism as well as a tentative pathway for fractionation of AMOX by CZ@T-GCN photocatalytic system were proposed in details. Only a marginal decrease in photocatalytic activity occurred after 5 consecutive tests. In an attempt to study the industrial applicability of catalyst, more than 79 % COD and 63 % TOC were eliminated under optimum conditions during 120 min illumination and the biodegradability of treated wastewater was also improved.

Engineered graphitic carbon nitride-based photocatalysts for visible-light-driven water splitting: A review

Abstract: Graphitic carbon nitride (g-C₃N₄), a polymeric semiconductor, has become a rising star for photocatalytic energy conversion because of its facile accessibility, metal-free nature, low cost, and environmentally benign properties. This work reviews the latest progress of g-C₃N₄-based materials in visible-light-driven water splitting to hydrogen. It begins with a brief history of g-C₃N₄, followed by various engineering strategies of g-C₃N₄, such as elemental doping, copolymerization, crystalline tailoring, surface engineering, and single-atom modification, for elevated photocatalytic water decomposition. In addition, the synthesis of g-C₃N₄ in different dimensions (0D, 1D, 2D, and 3D) and configurations of a series of g-C₃N₄-based heterojunctions (type II, Z-scheme, S-scheme, g-C₃N₄/metal, and g-C₃N₄/carbon heterojunctions) were also discussed for their improvement in photocatalytic hydrogen production. Lastly, the challenges and opportunities of g-C₃N₄-based nanomaterials are provided. It is anticipated that this review will promote the further development of the emerging g-C₃N₄-based materials for more efficiency in photocatalytic water splitting to hydrogen.

Potential Liquid-Organic Hydrogen Carrier (LOHC) Systems: A Review on Recent Progress

Abstract: The depletion of fossil fuels and rising global warming challenges encourage to find safe and viable energy storage and delivery technologies. Hydrogen is a clean, efficient energy carrier in various mobile fuel-cell applications and owned no adverse effects on the environment and human health. However, hydrogen storage is considered a bottleneck problem for the progress of the hydrogen economy. Liquid-organic hydrogen carriers (LOHCs) are organic substances in liquid or semi-solid states that store hydrogen by catalytic hydrogenation and dehydrogenation processes over multiple cycles and may support a future hydrogen economy. Remarkably, hydrogen storage in LOHC systems has attracted dramatically more attention than conventional storage systems, such as high-pressure compression, liquefaction, and absorption/adsorption techniques. Potential LOHC media must provide fully reversible hydrogen storage via catalytic processes, thermal stability, low melting points, favorable hydrogenation thermodynamics and kinetics, large-scale availability, and compatibility with current fuel energy infrastructure to practically employ these molecules in various applications. In this review, we present various considerable aspects for the development of ideal LOHC systems. We highlight the recent progress of LOHC candidates and their catalytic approach, as well as briefly discuss the theoretical insights for understanding the reaction mechanism.

In-situ synthesis of novel ternary CdS/PdAg/g-C3N4 hybrid photocatalyst with significantly enhanced hydrogen production activity and catalytic mechanism exploration

Abstract: Ternary CdS/PdAg/g-C3N4 hybrid photocatalyst was synthesized by a simple sonochemical method, and the sample exhibited excellent photocatalytic H2 evolution performance up to 3098.3 μmol g−1 h−1. This photocatalytic hydrogen production activity is 968.2 times higher than that of g-C3N4. Meanwhile, the apparent quantum yield (AQY) of the ternary hybrid photocatalyst is 9.6% at 420 nm. The extension of optical response range is verified by ultraviolet–visible diffuse reflectance spectra (DRS). Enhancement of the charge separation efficiency is examined via photoluminescence (PL), surface photovoltage (SPV) and electron spin resonance (ESR). A reasonable catalytic mechanism of the ternary hybrid photocatalyst is proposed. As an electron-bridge, PdAg bimetallic alloy NPs can assist the photoelectrons to transfer from the CB of g-C3N4 to the CB of CdS, from where the photoelectrons react with hydrogen ion to release hydrogen. This work may pave a new way on designing high efficient ternary hybrid photocatalyst.