The major obstacle for selective CO₂ photoreduction to C₂ hydrocarbons lies in the difficulty of C-C coupling, which is usually restrained by the repulsive dipole-dipole interaction between adjacent carbonaceous intermediates. Herein, we first construct semiconducting atomic layers featuring abundant Metalⁿ⁺-Metal^δ+ pair sites (0 < δ < n), aiming to tailor asymmetric charge distribution on the carbonaceous intermediates and hence trigger their C-C coupling for selectively yielding C₂ hydrocarbons. As an example, we first fabricate Co-doped NiS₂ atomic layers possessing abundant Ni²⁺-Ni^δ+ (0 < δ < 2) pairs, where Co doping strategy can ensure higher amount of Ni²⁺-Ni^δ+ pair sites. In-situ Fourier-transform infrared spectroscopy, quasi in-situ Raman spectroscopy and density-functional-theory calculations disclose the Ni²⁺-Ni^δ+ pair sites endow the adjacent CO intermediates with distinct charge densities, thus decreasing their dipole-dipole repulsion and hence lowering the rate-limiting C-C coupling reaction barrier. As a result, in simulated flue gas (10% CO₂ balance 90% N₂), the ethylene selectivity for Co-doped NiS₂ atomic layers reaches up to 74.3% with an activity of 70 µg·g⁻¹·h⁻¹, outperforming previously reported photocatalysts under similar operating conditions.

选择性CO _{2 光}还原成C ₂烃的主要障碍在于CC 耦合的困难，这通常受到相邻碳质中间体之间排斥偶极-偶极相互作用的限制。在此，我们首先构建半导体原子层设有丰富的金属^{Ñ +} -金属^{δ +}对网站（0 < δ < Ñ），旨在裁缝非对称电荷分布在碳质中间体，并因此触发用于选择性地产生Ç其CC联接₂烃。例如，我们首先制造了具有丰富 Ni ^{2+ 的}Co 掺杂 NiS ₂原子层-Ni ^{δ +} (0 < δ < 2) 对，其中 Co 掺杂策略可以确保更高数量的 Ni ²⁺ -Ni ^{δ +}对位点。原位傅立叶变换红外光谱、准原位拉曼光谱和密度泛函理论计算揭示了 Ni ²⁺ -Ni ^{δ +}对位点赋予相邻的 CO 中间体不同的电荷密度，从而降低它们的偶极-偶极排斥从而降低限速 CC 偶联反应势垒。因此，在模拟烟气中（10% CO ₂平衡 90% N ₂），Co掺杂的 NiS 的乙烯选择性_{2 个}原子层达到 74.3%，活性为 70 µg·g ^-1 ·h ^-1，在类似的操作条件下优于先前报道的光催化剂。