Effect of magnetic field on CO 2 conversion over Cu-ZnO/ZrO 2 catalyst in hydrogenation reaction Waleeporn Donphai a,b , Nuttanun Piriyawate a , Thongthai Witoon a,b , Pongsakorn Jantaratana c , Viganda Varabuntoonvit a , Metta Chareonpanich a,b, * a KU-Green Catalysts Group, Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900, Thailand b NANOTEC Center for Nanoscale Materials Design for Green Nanotechnology and Center for Advanced Studies in Nanotechnology for Chemical, Food and Agricultural Industries, Kasetsart University, Bangkok 10900, Thailand c Department of Physics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand A R T I C L E I N F O Article history: Received 5 April 2016 Received in revised form 28 June 2016 Accepted 18 July 2016 Available online xxx Keywords: Cu-ZnO/ZrO 2 Magnetic field CO 2 hydrogenation Cleaner production Carbon-neutral process A B S T R A C T Based on green and sustainable innovation with efficient utilization concepts for enhancement of catalyst performance and energy conservation, an external magnetic field has been applied in CO 2 hydrogenation reaction in order to improve catalytic activity and reduce the energy consumption. In this research, the performances of Cu-ZnO/ZrO 2 catalyst under magnetic field with different magnetic field intensities (0, 20.8, and 27.7 mT) and orientations (north-to-south (N-S) and south-to-north (S-N) directions) in CO 2 hydrogenation were investigated. Cu-ZnO/ZrO 2 catalysts operated under magnetic field gave higher CO 2 conversions, compared to that of without magnetic field at all reaction temperatures. The highest CO 2 conversions were obtained under the magnetic field condition at 20.8 mT in S-N direction which was 1.8–3.0 times higher than that of without magnetic field. Accordingly, the operating temperatures were significantly lower than those of without magnetic field at the same reaction rate. This outstanding performance could be attributed to the fact that the external magnetic field facilitated adsorption of CO 2 reactant gas molecules over the surface of magnetized catalysts. Accordingly, the challenge in application of magnetic field in CO 2 hydrogenation process help reduce CO 2 emission into the atmosphere compared to the convention reactor, and therefore led to the carbon-neutral CO 2 conversion process. ã 2016 Elsevier Ltd. All rights reserved. 1. Introduction An increase in global emissions of carbon dioxide (CO 2 ) over the last decades directly affected climate change and global warming [1,2]. Large amounts of CO 2 mainly come from the combustion of coal and fossil fuels in the industrial processes, and anthropogenic activities including electricity production, transportation, agricul- ture, and other man-made activities [3]. Several strategies of utilizing CO 2 as a raw material for syntheses of useful chemicals, fuels, alternative energy, and hydrocarbon feedstock can contrib- ute to solve global warming and climate change problems [4,5]. With high demand of energy worldwide, the development of green and alternative energy has become an important issue for energy and environmental sustainability [2,6]. CO 2 hydrogenation is considered as one of the important reactions due to the fact that methanol, dimethyl ether (DME), and chemical feedstock for petrochemical industries can be produced under low reaction temperature (lower than 300  C) through this reaction [7–9]. In particular, methanol is a clean alternative energy substitute to fossil fuel, reactant for biodiesel production, and chemical feedstock [10,11]. As is well known, Cu-ZnO/ZrO 2 catalyst is active and selective for the synthesis of methanol through CO 2 hydrogenation [3,10,12]. Cu based material is a promising catalyst for methanol synthesis due to its low cost, availability and good performance [9,12,13], while ZrO 2 helps facilitate Cu dispersion on the catalyst surface, leading to an enhancement of active Cu nanoparticles [2,12]. Moreover, ZnO can enhance the performance of Cu catalyst by increasing the active Cu surface in forms of Cu + and Cu 0 at the interaction surface of Cu and ZnO, which those Cu forms have been active for the methanol synthesis [13–15]. However, in order to cleaner produce the value-added hydrocar- bon products from CO 2 efficiently, the production process with less energy consumption has attracted much interest. * Corresponding author at: KU-Green Catalysts Group, Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900, Thailand. E-mail addresses: fengmtc@ku.ac.th, iamannmetta@gmail.com (M. Chareonpanich). http://dx.doi.org/10.1016/j.jcou.2016.07.007 2212-9820/ã 2016 Elsevier Ltd. All rights reserved. Journal of CO 2 Utilization 16 (2016) 204–211 Contents lists available at ScienceDirect Journal of CO 2 Utilization journa l homepage : www.e lsevier.com/loca te/jcou