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

doi:10.13801/j.cnki.fhclxb.20221128.001

光驱动的CoO_x/WO_3-x光热协同催化CO₂还原

doi: 10.13801/j.cnki.fhclxb.20221128.001

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，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，焦作 454003
3.
河南理工大学　化学化工学院，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
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- 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: 2022-11-28
- 刊出日期: 2023-09-15

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

YANG Juan^{1, 2, 3
, ,},
TIAN Ran^1
,,
WANG Dazhao¹,
DAI Jun^{1, 2},
DU Zhihua¹

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

Funds: National Natural Science Foundation of China (52074103; U2004194); Key Science and Technology Project of Henan Province (222102320095); Key Scientific Research Project of Henan Province Education Department (21 A440008)

摘要

摘要: 基于半导体光催化还原的人工光合成技术可在室温常压下将CO₂转化为碳基燃料，被认为是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不足、光生电荷复合快，致使CO₂光还原能量转换效率仍较低。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复合光催化剂，通过XRD、TEM、XPS、EPR和紫外-可见-近红外吸收光谱等测试技术对催化剂的晶相组成、微观形貌、光吸收特性与氧空位缺陷进行系统表征。CO₂光还原实验结果表明可见-近红外光照射3 h后，WO_3-x为催化剂仅可检测到3.2 μmol·g⁻¹的CH₄，复合CoO_x可显著提升WO_3-x的CO₂光催化还原性能，相同条件下最优催化剂2.5wt%CoO_x/WO_3-x的CO与CH₄产生量分别可达78.2和19.7 μmol·g⁻¹。引入氧空位可在WO_3-x的能带结构中形成一新的中间能级，增强近红外光吸收并使催化剂表面产生局部温升；复合CoO_x可在调控WO_3-x导带电势的同时，增强光生电荷的分离与迁移，光热效应和CoO_x助催化剂的协同作用是CO₂光催化转化性能增强的主要原因。此外，复合光催化剂CoO_x/WO_3-x具有优异的长期催化与结构稳定性。
- 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 2.5wt%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

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图 2 CoO_x/WO_3-x样品的XRD图谱

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

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图 3 (a) 单一WO_3-x的TEM图像；((b)~(d)) 2.5wt%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 2.5wt%CoO_x/WO_3-x sample

d—Distance

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

Figure 4. (a) HAADF-STEM image of 2.5wt%CoO_x/WO_3-x sample; ((b)-(d)) Element mapping images of 2.5wt%CoO_x/WO_3-x sample

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图 5 单一WO_3-x与2.5wt%CoO_x/WO_3-x的XPS全谱 (a)、W4f高分辨XPS图谱 (b) 和O1s高分辨XPS图谱 (c)、2.5wt%CoO_x/WO_3-x的Co2p高分辨XPS图谱 (d)

Figure 5. XPS survey spectra of bare WO_3-x and 2.5wt%CoO_x/WO_3-x (a), high-resolution W4f XPS spectra (b) and O1s XPS spectra of WO_3-x and 2.5wt%CoO_x/WO_3-x (c), high-resolution Co2p XPS spectrum of 2.5wt%CoO_x/WO_3-x (d)

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

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

g—Dimensionless factor

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

CB—Conduction band; VB—Valence band; IEL—Intermediate energy level; h—Planck constant; v—Frequency; α—Absorptivity index

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

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

NIR—Near infrared ray

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图 9 36 h CO₂光还原实验后2.5wt%CoO_x/WO_3-x催化剂的XRD图谱(插图为对应的TEM图像) (a) 和Co2p高分辨XPS谱图 (b)

Figure 9. XRD pattern (inset is the corresponding TEM image) (a) and high-resolution Co2p XPS spectra (b) of the used 2.5wt%CoO_x/WO_3-x catalyst after 36 h CO₂ photoreduction

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

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

C^-2—Reciprocal of interface capacitance squared; E_CB—Conduction band potential; E_fb—Flat band potential

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图 11 单一WO_3-x、2.5wt%CoO_x/WO_3-x和4.0wt%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, 2.5wt%CoO_x/WO_3-x and 4.0wt%CoO_x/WO_3-x samples

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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

VIS—Visible light

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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%
0.8wt%CoO_x/WO_3-x	0.8	0.79
1.6wt%CoO_x/WO_3-x	1.6	1.57
2.5wt%CoO_x/WO_3-x	2.5	2.48
3.2wt%CoO_x/WO_3-x	3.2	3.17
4.0wt%CoO_x/WO_3-x	4.0	3.95

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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

Photocatalyst	CO yield/(μmol·g⁻¹·h⁻¹)	CH₄ yield/(μmol·g⁻¹·h⁻¹)	Reaction condition	Reference
MoO_3-x	10.3	2.08	300 W Xe lamp UV-Vis-IR	[20]
Bi₂S₃/UiO-66	25.6	–	300 W Xe lamp UV-Vis-IR	[17]
C-doped WO_3-x	23.2	1.01	300 W Xe lamp an AM1.5 G filter	[36]
Bi₄TaO₈Cl/W₁₈O₄₉	23.42	–	180 mW/cm² solar light, 393 K	[42]
WO₃ nanosheets	–	1.19	300 W Xe lamp Visible light	[43]
TiO_2-x(A/B)-CoO_x	16.46	10.02	150 W UV lamp 393 K	[44]
WO₃/LaTiO₂N	2.21	0.36	300 W Xe lamp Visible light	[45]
WO_3-x/g-C₃N₄	8.3	–	500 W Xe lamp	[46]
2.5wt%CoO_x/WO_3-x	26.1	6.57	300 W Xe lamp Vis-NIR	This work

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