The challenge in the artificial photosynthesis of fossil resources from CO₂ by utilizing solar energy is to achieve stable photocatalysts with effective CO₂ adsorption capacity and high charge‐separation efficiency. A hierarchical direct Z‐scheme system consisting of urchin‐like hematite and carbon nitride provides an enhanced photocatalytic activity of reduction of CO₂ to CO, yielding a CO evolution rate of 27.2 µmol g⁻¹ h⁻¹ without cocatalyst and sacrifice reagent, which is >2.2 times higher than that produced by g‐C₃N₄ alone (10.3 µmol g⁻¹ h⁻¹). The enhanced photocatalytic activity of the Z‐scheme hybrid material can be ascribed to its unique characteristics to accelerate the reduction process, including: (i) 3D hierarchical structure of urchin‐like hematite and preferable basic sites which promotes the CO₂ adsorption, and (ii) the unique Z‐scheme feature efficiently promotes the separation of the electron–hole pairs and enhances the reducibility of electrons in the conduction band of the g‐C₃N₄. The origin of such an obvious advantage of the hierarchical Z‐scheme is not only explained based on the experimental data but also investigated by modeling CO₂ adsorption and CO adsorption on the three different atomic‐scale surfaces via density functional theory calculation. The study creates new opportunities for hierarchical hematite and other metal‐oxide‐based Z‐scheme system for solar fuel generation.

中文翻译：

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分层Z方案α-Fe2O3/ g-C3N4杂化物，可增强光催化二氧化碳还原能力

利用太阳能人工光合作用从CO _2中合成化石资源所面临的挑战是要获得具有有效CO ₂吸附能力和高电荷分离效率的稳定光催化剂。由顽童状赤铁矿和氮化碳组成的分层直接Z方案系统提供了增强的CO ₂还原为CO的光催化活性，在没有助催化剂和牺牲剂的情况下，CO的释放速率为27.2 µmol g ^-1 h ^-1比单独的g‐C ₃ N ₄（10.3 µmol g ^-1 h ^-1）高出2.2倍以上）。Z方案杂化材料增强的光催化活性可以归因于其加速还原过程的独特特征，包括：（i）顽童状赤铁矿的3D分层结构以及可促进CO ₂吸附的优选碱性位点，以及（ ii）独特的Z方案功能可有效促进电子-空穴对的分离，并增强g-C ₃ N ₄导带中电子的可还原性。这种分层Z方案明显优势的起源不仅基于实验数据进行了解释，而且还通过对CO ₂进行建模进行了研究。通过密度泛函理论计算，在三种不同原子尺度的表面上的吸附和一氧化碳吸附。这项研究为分层赤铁矿和其他基于金属氧化物的Z方案系统创造了新的机会，用于太阳能发电。