光驱动的CoOx/WO3-x光热协同催化CO2还原

杨娟; 田然; 王大钊; 戴俊; 杜智华

光驱动的CoO_x/WO_3-x光热协同催化CO₂还原

杨娟^{1, 2, 3, ,},
田然¹,
王大钊¹,
戴俊^{1, 2},
杜智华¹

1.
河南理工大学　安全科学与工程学院, 河南焦作 454003
2.
煤炭安全生产与清洁高效利用省部共建协同创新中心, 河南焦作 454003
3.
河南理工大学　化学化工学院, 河南焦作 454003

基金项目: 国家自然科学基金(52074103, U2004194)；河南省科技攻关重点项目(222102320095)；河南省教育厅重点科研项目(21 A440008)

详细信息

通讯作者:
杨娟，博士，教授，博士生导师，研究方向为光催化与能源化学　E-mail: yangjuan@hpu.edu.cn

中图分类号: O643.3
计量
- 文章访问数: 273
- HTML全文浏览量: 176
- 被引次数: 0
出版历程
- 收稿日期: 2022-10-10
- 修回日期: 2022-11-06
- 录用日期: 2022-11-12
- 网络出版日期: 2022-12-03

Light-driven photothermal synergistic catalytic CO₂ reduction over CoO_x/WO_3-x

Juan YANG^{1, 2, 3
, ,},
Ran TIAN¹,
Dazhao WANG¹,
Jun DAI^{1, 2},
Zhihua DU¹

1.
School of Safety Science and Engineering, Henan Polytechnic University, Henan Jiaozuo 454003, China
2.
State Collaborative Innovation Center of Coal Work Safety and Clean-efficiency Utilization, Henan Jiaozuo 454003, China
3.
School of Chemistry and Chemical Engineering, Henan Polytechnic University, Henan Jiaozuo 454003, China

Funds: National Natural Science Foundation of China (No.52074103, No.U2004194); Key Science and Technology Project of Henan Province (No.222102320095); Key Scientific Research Project of Henan Province Education Department (No.21 A440008)

摘要

摘要: 基于半导体光催化CO₂还原的人工光合成技术利用清洁可持续的太阳能，在室温常压下将CO₂转化为碳基燃料，被认为是可同时缓解能源短缺和环境危机的理想策略，但因已有光催化剂对太阳光利用率不足、光生电荷复合快，致使CO₂光还原能量转换效率仍较低，严重阻碍了其实际应用。本文采用水热法并结合表面浸渍过程首次制备出无定型CoO_x/WO_3-x复合催化剂，并研究了其在可见-近红外光(Vis-NIR)照射下的CO₂催化还原性能。氧空位的引入可调控WO_3-x的电子结构，在其能带结构中形成一新的中间能级(IEL)，产生近红外光响应与催化剂表面局部温升。复合助催化剂CoO_x可在调控WO_3-x导带电势的同时，经由捕获光空穴增强光生电荷的分离与迁移。上述两方面协同作用显著增强CoO_x/WO_3-x的CO₂光还原性能，最优催化剂2.5% CoO_x/WO_3-x可见-近红外光照射3h的CO与CH₄产生量分别可达78.2与19.7 μmol·g^-1，且Vis-NIR照射下的C1产物生成量大于NIR与Vis之和，表明CO₂还原性能的提升主要归因于光热协同催化，对设计光驱动的CO₂还原催化剂及光热协同催化体系具有重要理论指导意义。1不同光源照射条件下的CO₂还原产物生成量(a)和CoO_x/WO_3-x光热协同催化CO₂还原性能增强机制示意图(b)
- 光催化 /
- WO_3-x /
- CoO_x /
- CO₂光还原 /
- 光热协同
Abstract: The conversion of CO₂ into carbon-based fuels through artificial photosynthesis technology based on semiconductor photocatalytic reduction has been identified as an ideal strategy to alleviate energy shortage and environmental crisis. However, due to insufficient utilization of solar energy and rapid recombination of photogenerated charges for the reported photocatalysts, the energy conversion efficiency of CO₂ photoreduction is still low. Amorphous CoO_x/WO_3-x composite photocatalysts were synthesized by a hydrothermal method combining with surface impregnation process for the first time. Crystal phase composition, microstructure, optical absorption properties and oxygen vacancy defects of the prepared catalysts were systematically characterized by XRD, TEM, XPS, EPR and UV-Vis-NIR DRS. The results of CO₂ photoreduction experiments show that only 3.2 μmol·g⁻¹ CH₄ can be detected when using WO_3-x as a catalyst after Vis-NIR light irradiation for 3 h, whereas introducing CoO_x can significantly boost the CO₂ photocatalytic reduction performance of WO_3-x. Under the same experimental conditions, the yield of CO and CH₄ on 2.5% CoO_x/WO_3-x catalyst can reach 78.2 and 19.7 μmol·g⁻¹ respectively. Introducing oxygen vacancies can form a new intermediate energy level in the band structure of WO_3-x, which enhances NIR absorption and causes local temperature rise of the catalysts surface. Incorporating CoO_x contributes to enhance the separation and migration of photogenerated charges, and meanwhile can regulate the conduction-band potential of WO_3-x. The synergistic effect of photothermal effect and CoO_x cocatalyst is the primary reason for the promoted performance of CO₂ photocatalytic conversion. Additionally, the composite photocatalysts CoO_x/WO_3-x shows excellent long-term catalytic and structural stability.
- Photocatalysis /
- WO_3-x /
- CoO_x /
- CO₂ photoreduction /
- photothermal synergy

HTML全文

图 1 CoO_x/WO_3-x催化剂制备过程示意图

Figure 1. Schematic diagram of CoO_x/WO_3-x catalysts preparation process

下载: 全尺寸图片幻灯片

图 2 CoO_x/WO_3-x样品的XRD谱图

Figure 2. XRD patterns of CoO_x/WO_3-x samples

下载: 全尺寸图片幻灯片

图 3 (a) 单一WO_3-x的TEM图像；(b)~(d) 2.5% CoO_x/WO_3-x样品的TEM与HRTEM图像

Figure 3. (a) TEM image of bare WO_3-x; (b)~(d) TEM and HRTEM images of 2.5% CoO_x/WO_3-x sample

下载: 全尺寸图片幻灯片

图 4 (a) 2.5% CoO_x/WO_3-x样品的HAADF-STEM图与(b)~(d)对应的元素Mapping图

Figure 4. (a) HAADF-STEM, (b)~(d) element mapping images of 2.5% CoO_x/WO_3-x sample

下载: 全尺寸图片幻灯片

图 5 单一WO_3-x与2.5% CoO_x/WO_3-x的XPS全谱(a)、W 4f高分辨XPS谱(b)和O 1s高分辨XPS谱(c)、2.5% CoO_x/WO_3-x的Co 2p高分辨XPS谱(d)

Figure 5. XPS survey spectra of bare WO_3-x and 2.5% CoO_x/WO_3-x (a), high-resolution W 4f XPS spectra (b) and O 1s XPS spectra of WO_3-x and 2.5% CoO_x/WO_3-x (c), high-resolution Co 2p XPS spectrum of 2.5% CoO_x/WO_3-x (d)

下载: 全尺寸图片幻灯片

图 6 WO₃、WO_3-x与2.5% CoO_x/WO_3-x的室温ESR谱

Figure 6. Room temperature ESR spectra of WO₃, WO_3-x and 2.5% CoO_x/WO_3-x

下载: 全尺寸图片幻灯片

图 7 WO₃、WO_3-x与2.5% CoO_x/WO_3-x的紫外-可见-近红外吸收光谱(a)及相应的(αhv)²对hv曲线(b)~(d)

Figure 7. (a) UV-Vis-NIR absorption spectra of WO₃, WO_3-x and 2.5% CoO_x/WO_3-x, (b)~(d) the corresponding (αhv)² vs. hv curves

下载: 全尺寸图片幻灯片

图 8 (a) 不同反应条件下C1产物与O₂生成量，(b) 可见-近红外光照射下不同CoO_x/WO_3-x催化剂的C1产物生成量，(c) 不同光源照射条件下的C1产物生成量，(d) 可见-近红外光照射下2.5% CoO_x/WO_3-x的长期催化稳定性

Figure 8. Generation amount of C1 products and O₂ under different reaction conditions (a), generation amount of C1 products on different CoO_x/WO_3-x under Vis-NIR light (b) and under different light source irradiation (c), long-time catalytic stability of 2.5% CoO_x/WO_3-x under Vis-NIR light (d)

下载: 全尺寸图片幻灯片

图 9 36小时CO₂光还原实验后2.5% CoO_x/WO_3-x催化剂的(a) XRD谱图(插图为对应的TEM图像)，(b) Co 2p高分辨XPS谱图

Figure 9. (a) XRD pattern (inset is the corresponding TEM image) and (b) high-resolution Co 2p XPS spectrum of the used 2.5% CoO_x/WO_3-x catalyst after 36 h CO₂ photoreduction

下载: 全尺寸图片幻灯片

图 10 (a) WO_3-x与(b) 2.5% CoO_x/WO_3-x催化剂的莫特-肖特基曲线

Figure 10. Mott-Schottky plots of (a) WO_3-x and (b) 2.5% CoO_x/WO_3-x catalysts

C^-2−Reciprocal of interface capacitance squared, E_CB−conduction band potential, E_fb−flat band potential

下载: 全尺寸图片幻灯片

图 11 单一WO_3-x、2.5% CoO_x/WO_3-x和4.0% CoO_x/WO_3-x样品的瞬态光电流响应谱(a)与电化学阻抗谱(b)

Figure 11. Transient photocurrent response spectra (a) and electrochemical impedance spectra (b) of bare WO_3-x, 2.5% CoO_x/WO_3-x and 4.0% CoO_x/WO_3-x samples

下载: 全尺寸图片幻灯片

图 12 光驱动的CoO_x/WO_3-x光热协同催化CO₂还原性能增强机制示意图

Figure 12. Performance enhancing mechanism diagram of light driven photothermal synergistic catalytic CO₂ reduction over CoO_x/WO_3-x

下载: 全尺寸图片幻灯片

表 1 CoO_x/WO_3-x复合催化剂中Co元素的实测含量

Table 1. Actual content of Co element in CoO_x/WO_3-x composite catalysts

Sample	Addition content of Co/wt%		Measured content of Co/wt%
0.8% CoO_x/WO_3-x		0.8		0.79
1.6% CoO_x/WO_3-x		1.6		1.57
2.5% CoO_x/WO_3-x		2.5		2.48
3.2% CoO_x/WO_3-x		3.2		3.17
4.0% CoO_x/WO_3-x		4.0		3.95

下载: 导出CSV

表 2 CO₂光催化还原产物生成速率的比较

Table 2. Comparison of products generation rate for CO₂ photocatalytic reduction

Photocatalysts	CO yield/(μmol·g⁻¹·h⁻¹)	CH₄ yield/(μmol·g⁻¹·h⁻¹)	Reaction conditions	Reference
MoO_3-x	10.3	2.08	300 W Xe lamp UV-Vis-IR	J Mater Chem A 2019 Ref.[20]
Bi₂S₃/UiO-66	25.6	––	300 W Xe lamp UV-Vis-IR	Appl Catal B-Environ 2020 Ref.[17]
C-doped WO_3-x	23.2	1.01	300 W Xe lamp an AM1.5 G filter	ACS Catal 2022 Ref.[37]
Bi₄TaO₈Cl/W₁₈O₄₉	23.42	––	180 mW/cm² solar light, 393 K	Appl Catal B-Environ 2020 Ref.[42]
WO₃ nanosheets	––	1.19	300 W Xe lamp Visible light	ACS Appl Mater Inter 2012 Ref.[43]
TiO_2-x(A/B)-CoO_x	16.46	10.02	150 W UV lamp 393 K	Appl Catal B-Environ 2019 Ref. [44]
WO₃/LaTiO₂N	2.21	0.36	300 W Xe lamp Visible light	ACS Sustain Chem Eng 2021 Ref.[45]
WO_3-x/g-C₃N₄	8.3	––	500 W Xe lamp	ACS Omega 2019 Ref [46]
2.5% CoO_x/WO_3-x	26.1	6.57	300 W Xe lamp Vis-NIR	this work

下载: 导出CSV

[1]	SHARIFZADEH M, WANG L, SHAH N. Integrated biorefineries: CO₂ utilization for maximum biomass conversion[J]. Renewable Sustainable Energy Reviews,2015,47:151-161. doi: 10.1016/j.rser.2015.03.001
[2]	JIA J, QIAN C X, DONG Y C, et al. Heterogeneous catalytic hydrogenation of CO₂ by metal oxides: defect engineering-perfecting imperfection[J]. Chemical Society Reviews,2017,46:4631-4644. doi: 10.1039/C7CS00026J
[3]	SHEN H, GU Z X, ZHENG G F. Pushing the activity of CO₂ electroreduction by system engineering[J]. Science Bulletin,2019,64:1805-1816. doi: 10.1016/j.scib.2019.08.027
[4]	INOUE T, FUJISHIMA A, KONISHI S, et al. Photoelectrocatalytic reduction of carbon dioxide in aqueous suspensions of semiconductor powders[J]. Nature,1979,277:637-638. doi: 10.1038/277637a0
[5]	LI X, YU J G, JARONIEC M, et al. Cocatalysts for selective photoreduction of CO₂ into solar fuels[J]. Chemical Reviews,2019,119:3962-4179. doi: 10.1021/acs.chemrev.8b00400
[6]	JI Y, LUO Y. Theoretical study on the mechanism of photoreduction of CO₂ to CH₄ on the anatase TiO₂ (101) surface[J]. ACS Catalysis,2016,6(3):2018-2025. doi: 10.1021/acscatal.5b02694
[7]	ZHAO L, YE F, WANG D, et al. Lattice engineering on metal cocatalysts for enhanced photocatalytic reduction of CO₂ into CH₄[J]. ChemSusChem,2018,11(19):3524-3533. doi: 10.1002/cssc.201801294
[8]	LIU L, ZHAO H, ANDINO J M, et al. Photocatalytic CO₂ reduction with H₂O on TiO₂ nanocrystals: Comparison of anatase, rutile, and brookite polymorphs and exploration of surface chemistry[J]. ACS Catalysis,2012,2:1817-1828. doi: 10.1021/cs300273q
[9]	LI P, HU H F, LUO G, et al. Crystal facet-dependent CO₂ photoreduction over porous ZnO nanocatalysts[J]. ACS Applied Materials & Interfaces,2020,12:56039-56048.
[10]	WANG S H, ZHAN J W, CHEN K, et al. Potassium-doped g-C₃N₄ achieving efficient visible-light-driven CO₂ reduction[J]. ACS Sustainable Chemistry & Engineering,2020,8:22,8214-8222.
[11]	ZHANG Z J, LI L, JIANG Y, et al. Step-Scheme photocatalyst of CsPbBr₃ quantum dots/BiOBr nanosheets for efficient CO₂ photoreduction[J]. Inorganic Chemistry,2022,61(7):3351-3360. doi: 10.1021/acs.inorgchem.2c00012
[12]	CHO K M, KIM K H, PARK K, et al. Amine-functionalized graphene/CdS composite for photocatalytic reduction of CO₂[J]. ACS Catalysis,2017,7(10):7064-7069. doi: 10.1021/acscatal.7b01908
[13]	CAI X, ZHU M, ELBANNA O A, et al. Au nanorod photosensitized La₂Ti₂O₇ nanosteps: successive surface heterojunctions boosting visible to near-infrared photocatalytic H₂ evolution[J]. ACS Catalysis,2018,8:122-131. doi: 10.1021/acscatal.7b02972
[14]	LIU S, CHAI J, SUN S H, et al. Site-selective photosynthesis of Ag–AgCl@Au nanomushrooms for NIR-II light-driven O₂^- and O₂^·– evolving synergistic photothermal therapy against deep hypoxic tumors[J]. ACS Applied Materials & Interfaces,2021,13(39):46451-46463.
[15]	李成欣, 高助威, 刘钟馨, 等. 氧化石墨烯负载无纺布复合膜的制备及光热转换性能[J]. 复合材料学报, 2021, 38(12):4255-4264. doi: 10.13801/j.cnki.fhclxb.20210304.001 LI Chengxin, GAO Zhuwei, LIU Zhongxin, et al. Preparation of graphene oxide supported non-woven fabric composite membrane and its photothermal conversion performance[J]. Acta Materiae Compositae Sinica,2021,38(12):4255-4264(in Chinese). doi: 10.13801/j.cnki.fhclxb.20210304.001
[16]	MOON H K, LEE S H, CHOI H C. In vivo near-infrared mediated tumor destruction by photothermal effect of carbon nanotubes[J]. ACS Nano,2009,3(11):3707-3713. doi: 10.1021/nn900904h
[17]	CHEN X, LI Q, LI J J, et al. Modulating charge separation via in situ hydrothermal assembly of low content Bi₂S₃ into UiO-66 for efficient photothermocatalytic CO₂ reduction[J]. Applied Catalysis B:Environmental,2020,270:118915. doi: 10.1016/j.apcatb.2020.118915
[18]	LI R Y, ZHANG L B, SHI L, et al. MXene Ti₃C₂: An effective 2 D light-to-heat conversion material[J]. ACS Nano,2017,11(4):3752-3759. doi: 10.1021/acsnano.6b08415
[19]	KUWAHARA Y, YOSHIMURA Y, HAEMATSU K, et al. Mild deoxygenation of sulfoxides over plasmonic molybdenum oxide hybrid with dramatic activity enhancement under visible light[J]. Journal of the American Chemical Society,2018,140:9203-9210. doi: 10.1021/jacs.8b04711
[20]	LI J, YE Y, YE L, et al. Sunlight induced photo-thermal synergistic catalytic CO₂ conversion via localized surface plasmon resonance of MoO_3-x[J]. Journal of Materials Chemistry A,2019,7:2821-2830. doi: 10.1039/C8TA10922B
[21]	JI Y F, LUO Y. New mechanism for photocatalytic reduction of CO₂ on the anatase TiO₂(101) surface: The essential role of oxygen vacancy[J]. Journal of the American Chemical Society,2016,138(49):15896-15902. doi: 10.1021/jacs.6b05695
[22]	WANG M, SHEN M, JIN X X, et al. Oxygen vacancy generation and stabilization in CeO_2–x by Cu introduction with improved CO₂ photocatalytic reduction activity[J]. ACS Catalysis,2019,9(5):4573-4581. doi: 10.1021/acscatal.8b03975
[23]	LI X, WEN J, LOW J, et al. Design and fabrication of semiconductor photocatalyst for photocatalytic reduction of CO₂ to solar fuel[J]. Science China Materials,2014,57:70-100. doi: 10.1007/s40843-014-0003-1
[24]	LI X, YU J, JARONIEC M, et al. Cocatalysts for selective photoreduction of CO₂ into solar fuels[J]. Chemical Reviews,2019,119(6):3962-4179. doi: 10.1021/acs.chemrev.8b00400
[25]	WANG S Y, TERAMURA K, HISATOMI T, et al. Highly selective photocatalytic conversion of carbon dioxide by water over Al-SrTiO₃ photocatalyst modified with silver–metal dual cocatalysts[J]. ACS Sustainable Chemistry & Engineering,2021,9(28):9327-9335.
[26]	WANG Y, GODIN R, DURRANT J R, et al. Efficient hole trapping in carbon dot/oxygen-modified carbon nitride heterojunction photocatalysts for enhanced methanol production from CO₂ under neutral conditions[J]. Angewandte Chemie-International Edition,2021,60(38):20811-20816. doi: 10.1002/anie.202105570
[27]	WANG Y O, CHEN E Q, TANG J W. Insight on reaction pathways of photocatalytic CO₂ conversion[J]. ACS Catalysis,2022,12:7300-7316. doi: 10.1021/acscatal.2c01012
[28]	YIN G, NISHIKAWA M, NOSAKA Y, et al. Photocatalytic carbon dioxide reduction by copper oxide nanocluster-grafted niobate nanosheets[J]. ACS Nano,2015,9(2):2111-2119. doi: 10.1021/nn507429e
[29]	YAMAKATA A, KAWAGUCHI M, NISHIMURA N, et al. Behavior and energy states of photogenerated charge carriers on Pt- or CoO_x-loaded LaTiO₂N photocatalysts: Time-resolved visible to mid-infrared absorption study[J]. Journal of Physical Chemistry C,2014,118:23897-23906. doi: 10.1021/jp508233z
[30]	ZHANG H Y, GUO C F, REN J B, et al. Beyond CoO_x: a versatile amorphous cobalt species as an efficient cocatalyst for visible-light driven photocatalytic water oxidation[J]. Chemical Communications,2019,55:14050-14053. doi: 10.1039/C9CC07835E
[31]	ZHANG J, YU Z, GAO Z, et al. Porous TiO₂ nanotubes with spatially separated platinum and CoO_x cocatalysts produced by atomic layer deposition for photocatalytic hydrogen production[J]. Angewandte Chemie-International Edition,2017,56:816-820. doi: 10.1002/anie.201611137
[32]	BILLO T, FU F, RAGHUNATH P, et al. Ni-nanocluster modified black TiO₂ with dual active sites for selective photocatalytic CO₂ reduction[J]. Small,2018,14(2):1702928. doi: 10.1002/smll.201702928
[33]	YANG J, CHEN P Y, DAI J, et al. Solar-energy-driven conversion of oxygen-bearing low-concentration coal mine methane into methanol on full-spectrum-responsive WO_3-x catalysts[J]. Energy Conversion and Management,2021,247:114767. doi: 10.1016/j.enconman.2021.114767
[34]	刘颖琪, 翁文斌, 岑檠, 等. FeVO₄/Cu₃(BTC)₂(H₂O)₃异质结制备及光催化性能[J]. 复合材料学报, 2020, 37(12):3128-3136. LIU Yingqi, WENG Wenbin, CEN Qin, et al. Preparation and photocatalytic properties of FeVO₄/Cu₃(BTC)₂(H₂O)₃ heterojunction[J]. Acta Materiae Compositae Sinica,2020,37(12):3128-3136(in Chinese).
[35]	HUANG J W, ZHANG Y, DING Y. Rationally designed/constructed CoO_x/WO₃ anode for efficient photoelectrochemical water oxidation[J]. ACS Catalysis,2017,7(3):1841-1845. doi: 10.1021/acscatal.7b00022
[36]	ZHANG N, LI X Y, YE H C, et al. Oxide defect engineering enables to couple solar energy into oxygen activation[J]. Journal of the American Chemical Society,2016,138:8928-8935. doi: 10.1021/jacs.6b04629
[37]	LEI B, CUI W, CHEN P, et al. C−doping induced oxygen-vacancy in WO₃ nanosheets for CO₂ activation and photoreduction[J]. ACS Catalysis,2022,12:9670-9678. doi: 10.1021/acscatal.2c02390
[38]	MONIRUDDIN M, OPPONG E, STEWART D, et al. Designing CdS-based ternary heterostructures consisting of Co-metal and CoO_x cocatalysts for photocatalytic H₂ evolution under visible light[J]. Inorganic Chemistry,2019,58(18):12325-12333. doi: 10.1021/acs.inorgchem.9b01854
[39]	杨玉蓉, 王佳慧, 马远驰, 等. 双缺陷调控的Z型BiVO_4−x/g-C₃N_4−x异质结的制备及其光催化全解水[J]. 复合材料学报, 2022, 39(10):1-10. YANG Yurong, WANG Jiahui, MA Yuanchi, et al. Preparation of Z-scheme BiVO_4−x/g-C₃N_4−x heterojunction mediated by double defects and photocatalytic overall water splitting[J]. Acta Materiae Compositae Sinica,2022,39(10):1-10(in Chinese).
[40]	YANG J, HU S Y, FANG Y R, et al. Oxygen vacancy promoted O₂ activation over perovskite oxide for low-temperature CO oxidation[J]. ACS Catalysis,2019,9(11):9751-9763. doi: 10.1021/acscatal.9b02408
[41]	ZHENG Y F, FU K X, YU Z H, et al. Oxygen vacancies in a catalyst for VOCs oxidation: synthesis, characterization, and catalytic effects[J]. Journal of Materials Chemistry A,2022,10:14171-14186. doi: 10.1039/D2TA03180A
[42]	YAN J Y, WANG C H, MA H, et al. Photothermal synergic enhancement of direct Z-scheme behavior of Bi₄TaO₈Cl/W₁₈O₄₉ heterostructure for CO₂ reduction[J]. Applied Catalysis B:Environmental,2020,268:118401. doi: 10.1016/j.apcatb.2019.118401
[43]	CHEN X Y, ZHOU Y, LIU Q, et al. Ultrathin, single-crystal WO₃ nanosheets by two-dimensional oriented attachment toward enhanced photocatalystic reduction of CO₂ into hydrocarbon fuels under visible light[J]. ACS Applied Materials & Interfaces,2012,4:3372-3377.
[44]	LI Y Y, WANG C H, SONG M, et al. TiO_2-x/CoO_x photocatalyst sparkles in photothermo-catalytic reduction of CO₂ with H₂O steam[J]. Applied Catalysis B:Environmental,2019,243:760-770. doi: 10.1016/j.apcatb.2018.11.022
[45]	LIN N S, LIN Y, QIAN X J, et al. Construction of a 2 D/2 D WO₃/LaTiO₂N direct Z-Scheme photocatalyst for enhanced CO₂ reduction performance under visible light[J]. ACS Sustainable Chemistry & Engineering,2021,9(40):13686-13694.
[46]	HUANG S L, LONG Y J, RUAN S C, et al. Enhanced photocatalytic CO₂ reduction in defect-engineered Z-Scheme WO_3-x/g-C₃N₄ heterostructures[J]. ACS Omega,2019,4(13):15593-15599. doi: 10.1021/acsomega.9b01969
[47]	LI A, CAO Q, ZHOU G Y, et al. Three-phase photocatalysis for the enhanced selectivity and activity of CO₂ reduction on hydrophobic surface[J]. Angewandte Chemie International Edition,2019,58:14549-14555. doi: 10.1002/anie.201908058
[48]	YANG J, WANG X H, ZHAO X L, et al. Synthesis of uniform Bi₂WO₆-reduced graphene oxide nanocomposites with significantly enhanced photocatalytic reduction activity[J]. Journal of Physical Chemistry C,2015,119:3068-3078. doi: 10.1021/jp510041x