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abstract: Abstract Hollow heterostructured g C3N4@CeO2 photocatalysts with rich oxygen vacancies are controllable designed by a facile strategy. The synergetic effect and oxygen vacancies of g C3N4@CeO2 play the major role in the process of CO2 reduction, leading to CH4 generating much earlier and higher concentration than that of the pristine g C3N4 and CeO2 alone. Meanwhile, the unique hollow structures can make multiple reflections of light in the cavity, and thus enhance the utilization efficiency of light. Moreover, the L cysteine offers amine groups and meanwhile is anchored on the surface of g C3N4 during the synthesis process, and thus contributes greatly to the enhanced CO2 adsorption capability. Additionally, the large CO2 adsorption capability is also beneficial for the enhanced photocatalytic activity. Therefore, the novel photocatalysts exhibit a remarkable reduction performance for CO2 reduction under visible light irradiation. The g C3N4@CeO2 (CeO2 49.7 wt shows the highest yields of CH4 (3.5 mmol g 1) CH3OH (5.2 mmol g 1) and CO (16.8 mmol g 1) which are higher than most of other latest reported g C3N4 based photocatalysts for CO2 photoreduction, including coupled with semiconductors and noble metal cocatalysts. This strategy might represent a novel way for the effective conversion of CO2 to clean fuels and can also be great potential used in the energy and environmental science.
author_names: Mengfang Liang

Timur Borjigin

Yuhao Zhang

Beihong Liu

Hui Liu

Hong Guo
title: Controlled assemble of hollow heterostructured g C3N4@CeO2 with rich oxygen vacancies for enhanced photocatalytic CO2 reduction
venue: Applied Catalysis B: Environmental
year: 2019

abstract: Abstract Organic pollutants' treatment in wastewater has attracted extensive attention due to its degradation resistance and potentially hazardous to human health. Some organic matters such as persistent organic pollutants (POPs) could exist in environment and resist to decomposition, which may cause chronic intoxication or even cancers. Because photocatalytic technique is efficient, nontoxic, and cost effective to degrade organic pollutants, some semiconductors including TiO2 and ZnO as photocatalysts have aroused wide public concern. CeO2 has been reported as an efficient photocatalyst in contrast to TiO2 owing to its high oxygen storage, eco friendly properties and photostability. But inefficient utilization of solar energy due to its intrinsic wide bandgap restrains its further application in real environmental pollutant treatment. In order to improve photocatalytic performances of CeO2, some modifications have been developed such as doping ions, coupling with semiconductor and construction of CeO2 based solid solution. The purpose of this review is to introduce these techniques, reveals its fundamental mechanisms and the recent researches about photodegradation of organic pollutants in wastewater over CeO2 based photocatalysts. Besides, this review will evaluate the photocatalytic performance for organic pollutants and outlook the challenges and prospects in the future.
author_names: Ran Ma

Sai Zhang

Tao Wen

Pengcheng Gu

Lei Li

Guixia Zhao

Fenlei Niu

Qifei Huang

Zhenwu Tang

Xiangke Wang
title: A critical review on visible light response CeO2 based photocatalysts with enhanced photooxidation of organic pollutants
venue: Catalysis Today
year: 2019

abstract: Highly efficient photocatalysts are urgently needed with the ever increasing problems of environmental pollution and the energy crisis. Herein, we report a shape controlled binary photocatalyst consisting of S doped CeO2 hollow spheres sensitized with ultrathin CdS shells. The core shelled CeO2 xSx@CdS composite is synthesized using a simple template assisted method followed by anion exchange and chemical bath deposition processes. Owing to the reduced band gap caused by the oxygen vacancies in the S doped CeO2, and the CdS sensitization effect accelerating the interface carrier separation and transfer, the CeO2 xSx@CdS composite exhibits superior photocatalytic activity for hydrogen evolution (1147.2 mmol g 1 h 1) under visible light illumination, which is 4.4, 11.1 and 94.8 times higher than that of CdS (258.2 mmol g 1 h 1) CeO2 xSx (103.0 mmol g 1 h 1) and CeO2 (12.1 mmol g 1 h 1) respectively. In addition, the composite displays highly efficient organic pollutant degradation (99.8% degradation of RhB within 25 min)
author_names: Ningchao Zheng

Ting Ouyang

Yibo Chen

Zhu Wang

Di-yun Chen

Zhao-Qing Liu
title: Ultrathin CdS shell sensitized hollow S doped CeO2 spheres for efficient visible light photocatalysis
year: 2019

abstract: Abstract Pd/CeO2 is an active component in emission control catalysts for CO oxidation. Nanostructured CeO2 powders can be prepared in the form of rods exposing predominantly (111) surfaces and cubes exposing (100) surfaces. While differences in the reactivity of Pd supported on these facets of ceria have been reported, the origins of the reactivity differences are not well understood. Pd supported on (111) surfaces of ceria rods exhibits room temperature CO oxidation activity, while Pd on (100) surface of ceria cubes shows comparable activity at a temperature that is 60 degC higher. Earlier, we established that Pd/CeO2 rods are active due to a Langmuir Hinshelwood mechanism involving isolated Pd atoms in the form of Pd1O and Pd1O2 species. Here, we establish using in situ CO IR spectroscopy and density functional theory (DFT) that, in addition to TEM visible Pd nanoparticles, Pd/CeO2 cubes also contain isolated Pd species, predominantly in the form of Pd1O. DFT calculations show that CO oxidation proceeds via a Mars van Krevelen pathway, which is possible for the (100) surface because of the lower Ce O binding energy compared to the (111) surface. Overall, the catalytic cycle for CO oxidation on Pd/CeO2(100) involves a higher free energy barrier than on Pd/CeO2(111) in keeping with the experimentally observed activity difference. EXAFS measurements show that the active Pd phase in both Pd/CeO2 rods and Pd/CeO2 cubes responds dynamically with respect to reducing and oxidizing conditions. The redispersion of Pd in oxidative conditions is more pronounced for Pd/CeO2 rods and the catalyst is more active after an oxidative treatment.
author_names: Giulia Spezzati

Angelica Benavidez

Andrew DeLaRiva

Yaqiong Su

Jan Philipp Hofmann

Shunsuke Asahina

E J Olivier

Johannes H Neethling

Jeffrey T Miller

Abhaya K Datye

Emiel J M Hensen
title: CO oxidation by Pd supported on CeO2(100) and CeO2(111) facets
venue: Applied Catalysis B: Environmental
year: 2019

abstract: Stable catalysts through steaming The lifetime of catalysts that convert automotive exhaust pollutants can be increased by lowering their operating temperature, which helps to prevent deactivation caused by the active metal atoms agglomerating into larger, less active particles. Nie et al. show that a thermally stable catalyst, atomically dispersed Pt2+ on CeO2, can become active for CO oxidation at 150degC after steam treatment at 750degC. In studies with simulated vehicle exhaust, this catalyst treatment also improves its oxidation activity for other exhaust components such as hydrocarbons. Science, this issue p. 1419 Steam treatment at 750degC transforms single Pt2+ ions on CeO2 into a CO oxidation catalyst active at low temperatures. To improve fuel efficiency, advanced combustion engines are being designed to minimize the amount of heat wasted in the exhaust. Hence, future generations of catalysts must perform at temperatures that are 100degC lower than current exhaust treatment catalysts. Achieving low temperature activity, while surviving the harsh conditions encountered at high engine loads, remains a formidable challenge. In this study, we demonstrate how atomically dispersed ionic platinum (Pt2+ on ceria (CeO2) which is already thermally stable, can be activated via steam treatment (at 750degC) to simultaneously achieve the goals of low temperature carbon monoxide (CO) oxidation activity while providing outstanding hydrothermal stability. A new type of active site is created on CeO2 in the vicinity of Pt2+ which provides the improved reactivity. These active sites are stable up to 800degC in oxidizing environments.
author_names: Lei Nie

Donghai Mei

Haifeng Xiong

Boaxing Peng

Zhibo Ren

Xavier Isidro Pereira Hernandez

Andrew DeLaRiva

Meng Wang

Mark H Engelhard

Libor Kovarik

Abhaya K Datye
title: Activation of surface lattice oxygen in single atom Pt/CeO2 for low temperature CO oxidation
venue: Science
year: 2017

abstract: Abstract Ceria (CeO2) with abundant oxygen defects, surface alkalinity, low cost effectiveness and admirable redox ability could be used in the photoreduction of CO2. However, little attention has been paid to the interaction of reactant CO2 molecules on CeO2 based photocatalysts. In this work, Cu2O nanoparticles were applied to the modification of the properties of Lewis acid/base, surface oxygen defect content and visible light adsorption of CeO2, and the adsorption/activation abilities of CO2 reactant on Cu2O/CeO2 and CeO2 photocatalysts were investigated in comparison. The photocatalytic performance showed that Cu2O/CeO2 had better activity than CeO2. And the loading of Cu2O resulted in more oxygen defects and Ce3+ species, which was helpful for available visible light adsorption and higher charge separation efficiency. Furthermore, CO2 TPD, CO2 adsorption DRIFTS and in situ ESR results demonstrated that the synergistic effects of Cu2O/CeO2 were beneficial for more generated carboxylate and CO2 radicals, instead of carbonate species which promoted CO2 reduction to CO.
author_names: Yu Pu

Yidan Luo

Xiaoqian Wei

Jingfang Sun

Lulu Li

Weixin Zou

Lin Dong
title: Synergistic effects of Cu2O decorated CeO2 on photocatalytic CO2 reduction: Surface Lewis acid/base and oxygen defect
venue: Applied Catalysis B: Environmental
year: 2019

abstract: Here, we report the synthesis of Cu doped CeO2 nanorods (denoted as Cu CeO2 x, x represents the mass content (wt% of the doped Cu) by a facile hydrothermal method, followed by thermal treatment in an H2/Ar atmosphere. As the electrocatalyst, Cu CeO2 3.9 with a large surface area of 95.2 m2 g 1 and mesoporous structure exhibits high electrocatalytic activity toward the N2 reduction reaction (NRR) delivering an NH3 yield rate of 5.3 x 10 10 mol s 1 cm 2 and a faradaic efficiency of 19.1% at 0.45 V (vs. RHE) in a 0.1 M Na2SO4 electrolyte (pH 6.3) much higher than the NRR performance achieved with pure CeO2 nanorods. The Cu doping can effectively tune the concentration of multiple oxygen vacancies in CeO2, thus resulting in significantly improved NRR activity.
author_names: Shengbo Zhang

Cuijiao Zhao

Yanyan Liu

Wenyi Li

Jialu Wang

Guozhong Wang

Yunxia Zhang

Haimin Zhang

Huijun Zhao
title: Cu doping in CeO2 to form multiple oxygen vacancies for dramatically enhanced ambient N2 reduction performance.
venue: Chemical communications
year: 2019

abstract: Abstract Manipulating interfacial structure and interaction between metal and supports is important for many heterogenous catalysts with the aim at achieving high and stable activity and selectivity. In this work, two kinds of Ni/CeO2 SiO2 catalysts are fabricated and designed, including CeO2 close contact with Ni nanoparticles (Ni/CeO2 SiO2 P) or CeO2 away from Ni nanoparticles (Ni/CeO2 SiO2 C) for dry reforming of methane. Ni/CeO2 SiO2 P exhibits superior low temperature activity and H2/CO ratio compared with Ni/CeO2 SiO2 C. CO2 and CH4 conversions on the former (87.3% and 78.5% are higher than those of the later (80.5% and 67.8% at 700 degC. Meanwhile, Ni/CeO2 SiO2 P is stable in the long term study whereas Ni/CeO2 SiO2 C presents poor stability and the activity dramatically decreases in 10 h. The improved performance and stability on Ni/CeO2 SiO2 P originates from more reactive oxygen species and more accessible sites for the formate species on the metal support interface. The reaction order and activation energy of both catalysts are also calculated in the kinetic studies. This work opens up new possibilities for exploring the effect of metal support on designing highly efficient heterogeneous catalysts.
author_names: Xiaoliang Yan

Tong Hu

Peng Liu

Sha Sha Li

Binran Zhao

Qian Zhang

Wei Jiao

Shuai Chen

Pengfei Wang

Jingjun Lu

Xiaonan Deng

Yun-Xiang Pan
title: Highly efficient and stable Ni/CeO2 SiO2 catalyst for dry reforming of methane: Effect of interfacial structure of Ni/CeO2 on SiO2
venue: Applied Catalysis B: Environmental
year: 2019

abstract: Electrocatalytic oxygen evolution reaction (OER) is a key process in electrochemical energy conversion and storage. Cobalt containing spinel oxides are promising candidates for OER, but suffer from.
author_names: Bocheng Qiu

Cong Wang

Ning Zhang

Lejuan Cai

Yujie Xiong

Yang Chai
title: CeO2 Induced Interfacial Co2+ Octahedral Sites and Oxygen Vacancies for Water Oxidation
venue: ACS Catalysis
year: 2019

abstract: Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40(th) anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three way catalysts (TWCs) Apart from this well established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2 based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2 based materials has already been acquired, new characterization techniques and powerful theoretical methods are deepening our understanding of these materials, helping us to predict their behavior and application potential. This review has a wide view on all those aspects related to ceria which promise to produce an important impact on our life, encompassing fundamental knowledge of CeO2 and its properties, characterization toolbox, emerging features, theoretical studies, and all the catalytic applications, organized by their degree of establishment on the market.
author_names: Tiziano Montini

Michele Melchionna

Matteo Monai

Paolo Fornasiero
title: Fundamentals and Catalytic Applications of CeO2 Based Materials.
venue: Chemical reviews
year: 2016