Spinel ZnFe₂O₄ microspheres coupled with Ag/TiO₂ nanorods (NRs) to develop Z-scheme heterojunction were fabricated using a facile hydrothermal approach and were tested for photocatalytic CO₂ conversion to fuels. ZnFe₂O₄/Ag/TiO₂ NRs composite presents remarkably improved CO₂ photo-activity for CO production, which was 1.49 folds higher than ZnFe₂O₄/TiO₂ NRs and 4.12 times that using pristine ZnFe₂O₄ microspheres. Similar trends were obtained to produce methane and methanol over composite catalyst. Selective CO and hydrocarbon fuels production was obviously due to double charge transfer approach in indirect Z-scheme heterojunction with superior charge carrier separation and high visible light absorption. Interestingly, CO evolution under visible-light with ZnFe₂O₄/Ag/TiO₂ NRs was declined by 7.48 folds than using UV-light irradiation. This was apparently due to the inappropriate VB position of ZnFe₂O₄ for stimulating CO₂ reduction under visible light irradiation. Comparing morphological effects, coupling TiO₂ NRs with Ag/ZnFe₂O₄, production of CO was 1.40 folds higher than using TiO₂ NPs with Ag/ZnFe₂O₄ composite due to 1D TiO₂ NRs and ZnF₂O₄ were beneficial for promoting charge carrier separation. This work provides a new approach for preparing ZnFe₂O₄ based structured Z-scheme hetero-junction for stimulating photocatalytic conversion of CO₂ to selective fuels and would be promising for energy application.

尖晶石ZnFe ₂ O ₄微球与Ag / TiO ₂纳米棒（NRs）偶联形成Z型异质结，采用一种简便的水热方法制备，并进行了光催化CO ₂转化为燃料的测试。ZnFe ₂ O ₄ / Ag / TiO ₂ NRs复合材料显着改善了CO生产的CO ₂光活性，是ZnFe ₂ O ₄ / TiO ₂ NRs的1.49倍，是使用原始ZnFe ₂ O _4的4.12倍微球。获得了在复合催化剂上生产甲烷和甲醇的类似趋势。选择性生产CO和烃类燃料显然是由于间接Z方案异质结中的双重电荷转移方法，具有优异的载流子分离和高可见光吸收率。有趣的是，与使用紫外线相比，使用ZnFe ₂ O ₄ / Ag / TiO ₂ NRs在可见光下的CO释放量减少了7.48倍。显然，这是由于ZnFe ₂ O _4的VB位置不合适以刺激可见光照射下的CO ₂还原。比较形态学效果，将TiO ₂ NRs与Ag / ZnFe ₂偶联O ₄，由于一维TiO ₂ NR和ZnF ₂ O ₄有利于促进电荷载流子的分离，因此与含Ag / ZnFe ₂ O ₄复合物的TiO ₂ NP相比，CO的产量高1.40倍。这项工作提供了一种新的方法来制备基于ZnFe ₂ O ₄的结构化Z型异质结，以促进CO ₂向选择性燃料的光催化转化，并且有望应用于能源领域。