Waleeporn Donphai

Bio: Waleeporn Donphai is an academic researcher from Kasetsart University. The author has contributed to research in topics: Catalysis & Methanol. The author has an hindex of 14, co-authored 29 publications receiving 691 citations. Previous affiliations of Waleeporn Donphai include Osaka University.

High performance visible-light responsive Chl-Cu/ZnO catalysts for photodegradation of rhodamine B

Abstract: The photocatalytic degradation of rhodamine B (RhB) over chlorophyll-Cu co-modified ZnO catalysts (Chl-Cu/ZnO) was studied under visible-light irradiation. It was found that chlorophyll as an electron donor and copper in Cu2+ form help inhibit the recombination of electron-hole pairs and improve photoactivity of the catalyst. The synergistic effect between chlorophyll and Cu was found to improve visible-light response of ZnO nanoparticles, resulting in excellent performance in photodegradation of RhB. The appropriate ratio of chlorophyll and Cu loadings over ZnO was 0.5Chl-0.10Cu/ZnO—at this ratio, under visible-light irradiation of 2 h, the degradation efficiency was approximately 99% (60 mg/l of RhB solution), of which 18% of RhB adsorption occurred in dark condition. Moreover, outstanding reusability of Chl-Cu/ZnO, for up to six cycles, was found, with more than 80% degradation efficiency.

Recent Advances in Carbon Dioxide Hydrogenation to Methanol via Heterogeneous Catalysis.

Abstract: The utilization of fossil fuels has enabled an unprecedented era of prosperity and advancement of well-being for human society. However, the associated increase in anthropogenic carbon dioxide (CO2) emissions can negatively affect global temperatures and ocean acidity. Moreover, fossil fuels are a limited resource and their depletion will ultimately force one to seek alternative carbon sources to maintain a sustainable economy. Converting CO2 into value-added chemicals and fuels, using renewable energy, is one of the promising approaches in this regard. Major advances in energy-efficient CO2 conversion can potentially alleviate CO2 emissions, reduce the dependence on nonrenewable resources, and minimize the environmental impacts from the portions of fossil fuels displaced. Methanol (CH3OH) is an important chemical feedstock and can be used as a fuel for internal combustion engines and fuel cells, as well as a platform molecule for the production of chemicals and fuels. As one of the promising approaches, thermocatalytic CO2 hydrogenation to CH3OH via heterogeneous catalysis has attracted great attention in the past decades. Major progress has been made in the development of various catalysts including metals, metal oxides, and intermetallic compounds. In addition, efforts are also put forth to define catalyst structures in nanoscale by taking advantage of nanostructured materials, which enables the tuning of the catalyst composition and modulation of surface structures and potentially endows more promising catalytic performance in comparison to the bulk materials prepared by traditional methods. Despite these achievements, significant challenges still exist in developing robust catalysts with good catalytic performance and long-term stability. In this review, we will provide a comprehensive overview of the recent advances in this area, especially focusing on structure-activity relationship, as well as the importance of combining catalytic measurements, in situ characterization, and theoretical studies in understanding reaction mechanisms and identifying key descriptors for designing improved catalysts.

State of the art and perspectives in heterogeneous catalysis of CO2 hydrogenation to methanol.

Abstract: The ever-increasing amount of anthropogenic carbon dioxide (CO2) emissions has resulted in great environmental impacts. The selective hydrogenation of CO2 to methanol, the first target in the liquid sunshine vision, not only effectively mitigates the CO2 emissions, but also produces value-added chemicals and fuels. This critical review provides a comprehensive view of the significant advances in heterogeneous catalysis for methanol synthesis through direct hydrogenation of CO2. The challenges in thermodynamics are addressed first. Then the progress in conventional Cu-based catalysts is discussed in detail, with an emphasis on the structural, chemical, and electronic promotions of supports and promoters, the preparation methods and precursors of Cu-based catalysts, as well as the proposed models for active sites. We also provide an overview of the progress in noble metal-based catalysts, bimetallic catalysts including alloys and intermetallic compounds, as well as hybrid oxides and other novel catalytic systems. The developments in mechanistic aspects, reaction conditions and optimization, as well as reactor designs and innovations are also included. The advances in industrial applications for methanol synthesis are further highlighted. Finally, a summary and outlook are provided.

Piezo‐Catalytic Effect on the Enhancement of the Ultra‐High Degradation Activity in the Dark by Single‐ and Few‐Layers MoS2 Nanoflowers

Abstract: Single- and few-layer MoS2 nanoflowers are first discovered to have a piezo-catalyst effect, exhibiting an ultra-high degradation activity in the dark by introducing external mechanical strains. The degradation ratio of the Rhodamine-B dye solution reaches 93% within 60 s under ultrasonic-wave assistance in the dark.

Dry reforming of methane over Ni/La2O3 nanorod catalysts with stabilized Ni nanoparticles

Abstract: This paper describes the design of a Ni/La2O3 catalyst using La2O2CO3 nanorod as a support precursor (denoted as Ni/La2O3-LOC) via a wet impregnation method for dry reforming of methane (DRM). The results showed that La2O3 derived from the La2O2CO3 precursor maintained its initial morphology upon thermal treatment and could highly disperse Ni particles on it. Additionally, the nanorod-shaped support could provide more medium-strength basic sites to facilitate CO2 adsorption and activation on its surface. Consequently, the Ni/La2O3-LOC catalyst reached 70% of CH4 conversion and 75% of CO2 conversion at 700 °C after 50 h DRM reaction with a H2/CO ratio of 0.87. The enhanced metal-support interaction restricted the sintering of nickel particles under harsh reaction conditions. Coke evolution on the catalysts was also investigated to understand coke formation mechanism and the role of La2O2CO3 in coke elimination. It has been found that nickel dispersion can affect distribution of coke and La2O2CO3 on the surface of catalyst, both of which have a close relation with catalytic performance.