碱热处理SnO2/g-C3N4催化还原CO2的影响机制研究

苏明雪; 顾春晗; 张涵; 李宁

doi:10.13205/j.hjgc.202602017

碱热处理SnO₂/g-C₃N₄催化还原CO₂的影响机制研究

doi: 10.13205/j.hjgc.202602017

苏明雪^1,2,
顾春晗^1,2,
张涵^1,2,
李宁^1,2

1. 合肥水泥研究设计院有限公司, 合肥 230022;
2. 水泥制造绿色低碳技术安徽省重点实验室, 合肥 230022

基金项目:

中国中材国际工程股份有限公司前沿科学开放基金 “水泥窑烟气CO2电化学还原制甲酸关键技术研究”

详细信息

作者简介:
苏明雪（1993—），男，高级工程师，主要研究方向为固废资源化及碳捕集利用。smx@hcrdi.com

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出版历程
- 收稿日期: 2025-05-08
- 网络出版日期: 2026-04-11
- 刊出日期: 2026-02-01

Research on mechanism of catalytic reduction of CO₂ by alkali-heat treated SnO₂/g-C₃N₄

SU Mingxue^1,2,
GU Chunhan^1,2,
ZHANG Han^1,2,
LI Ning^1,2

1. Hefei Cement Research & Design Institute Corporation Ltd., Hefei 230022, China;
2. Anhui Key Laboratory of Green and Low-Carbon Technology in Cement Manufacturing, Hefei 230022, China

摘要

摘要: 电催化还原CO₂是我国实现“双碳”战略的重要途经。石墨相氮化碳（g-C₃N₄）由于其原料来源广泛、制备工艺简单、成本低廉，在电催化领域被广泛用于催化剂或载体。针对g-C₃N₄作为CO₂电还原（eCO₂RR）催化剂载体，存在比表面积小、碱性弱以及实际烟气中低浓度CO₂和O₂竞争还原的瓶颈，研究提出通过碱热处理改性SnO₂/g-C₃N₄复合催化剂的技术路线。XPS和CO₂-TPD等表征结果表明：碱热处理显著提升了g-C₃N₄载体的表面氨基含量（由3.7%增至7.0%），增强了催化剂整体碱性及CO₂吸附能力（由7.69 mmol/g增至48.80 mmol/g）。碱热处理诱导电子从g-C₃N₄中的N元素向Sn活性位点加速转移，形成富电子态Sn中心，并产生更多氧空位，协同促进了CO₂的活化与还原。竞争吸附实验表明，改性后的SnO₂/CNOHHT在CO₂/O₂混合气中对CO₂具有更高的选择性吸附（分离系数0.90），有利于在反应界面形成CO₂富集微环境，抑制O₂还原竞争反应。电催化性能测试显示，在纯CO₂气氛下，SnO₂/CNOHHT电催化还原制甲酸的法拉第效率高达80.5%（电流密度23.5 mA/cm²）；在含4% O₂的模拟烟气氛围下，其甲酸法拉第效率仍可达59.4%，显著优于未改性及碱处理的催化剂。研究为开发适用于实际含氧烟气CO₂高效电还原的g-C₃N₄基催化剂提供了新思路。
- CO₂电还原 /
- 氧化锡 /
- 石墨相氮化碳 /
- 烟气 /
- 传质强化
Abstract: Electrocatalytic reduction of CO₂ （eCO₂RR） is a crucial pathway for China to achieve its "Carbon Peak and Carbon Neutrality" goals. Graphitic carbon nitride （g-C₃N₄） is widely employed as a catalyst or catalyst support in electrocatalysis due to its abundant raw materials， simple preparation process， and low cost. However， g-C₃N₄， when used as a catalyst support for eCO₂RR， faces bottlenecks such as low specific surface area， weak alkalinity， and competitive reduction of low-concentration CO₂ and O₂ in actual flue gas. Therefore， this study proposed a modification strategy for SnO₂/g-C₃N₄ composite catalysts through alkali-thermal treatment. Characterization techniques such as XPS and CO₂-TPD revealed that the alkali-thermal treatment significantly increased the surface amino group content of the g-C₃N₄ support （from 3.7% to 7.0%）， enhancing the overall alkalinity and CO₂ adsorption capacity of the catalyst （from 7.69 mmol/g to 48.80 mmol/g）. This treatment accelerated electron transfer from N atoms in g-C₃N₄ to Sn active sites， forming electron-rich Sn centers and generating more oxygen vacancies. These effects synergistically promoted the activation and reduction of CO₂. Competitive adsorption experiments demonstrated that SnO₂/CNOHHT exhibited a higher adsorption capacity for CO₂ than for O₂ in a CO₂/O₂ mixture （with a separation factor of 0.90）. This selectivity favors the formation of a CO₂-enriched microenvironment at the reaction interface， thereby suppressing the competitive oxygen reduction reaction （ORR）. Electrocatalytic performance tests showed that under a pure CO₂ atmosphere， SnO₂/CNOHHT achieved a high Faradaic efficiency （FE） of 80.5% for formate production at a current density of 23.5 mA/cm². Remarkably， in a simulated flue gas atmosphere containing 4% O₂， it still maintained a FE for formate of 59.4%， significantly outperforming both the unmodified and the alkali-treated-only catalysts. This study provides new insight for developing g-C₃N₄-based eCO₂RR catalysts suitable for practical oxygen-containing flue gas conditions.
- CO₂ electroreduction /
- SnO₂ /
- graphitic carbon nitride /
- flue gas /
- mass transfer enhancement

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