Abstract2D metal organic frameworks (MOF) have received tremendous attention due to their organic–inorganic hybrid nature, large surface area, highly exposed active sites, and ultrathin thickness. However, the application of 2D MOF in light‐to‐hydrogen (H2) conversion is rarely reported. Here, a novel 2D MOF [Ni(phen)(oba)]n·0.5nH2O (phen = 1,10‐phenanthroline, oba = 4,4′‐oxybis(benzoate)) is for the first time employed as a general, high‐performance, and earth‐abundant platform to support CdS or Zn0.8Cd0.2S for achieving tremendously improved visible‐light‐induced H2‐production activity. Particularly, the CdS‐loaded 2D MOF exhibits an excellent H2‐production activity of 45 201 µmol h−1 g−1, even exceeding that of Pt‐loaded CdS by 185%. Advanced characterizations, e.g., synchrotron‐based X‐ray absorption near edge structure, and theoretical calculations disclose that the interactive nature between 2D MOF and CdS, combined with the high surface area, abundant reactive centers, and favorable band structure of 2D MOFs, synergistically contribute to this distinguished photocatalytic performance. The work not only demonstrates that the earth‐abundant 2D MOF can serve as a versatile and effective platform supporting metal sulfides to boost their photocatalytic H2‐production performance without noble‐metal co‐catalysts, but also paves avenues to the design and synthesis of 2D‐MOF‐based heterostructures for catalysis and electronics applications.

Direct experimental observations of the interface structure can provide vital insights into heterogeneous catalysis. Examples of interface design based on single atom and surface science are, however, extremely rare. Here, we report Cu–Sn single-atom surface alloys, where isolated Sn sites with high surface densities (up to 8%) are anchored on the Cu host, for efficient electrocatalytic CO2 reduction. The unique geometric and electronic structure of the Cu–Sn surface alloys (Cu97Sn3 and Cu99Sn1) enables distinct catalytic selectivity from pure Cu100 and Cu70Sn30 bulk alloy. The Cu97Sn3 catalyst achieves a CO Faradaic efficiency of 98% at a tiny overpotential of 30 mV in an alkaline flow cell, where a high CO current density of 100 mA cm−2 is obtained at an overpotential of 340 mV. Density functional theory simulation reveals that it is not only the elemental composition that dictates the electrocatalytic reactivity of Cu–Sn alloys; the local coordination environment of atomically dispersed, isolated Cu–Sn bonding plays the most critical role.

Closing both the carbon and nitrogen loops is a critical venture to support the establishment of the circular, net‐zero carbon economy. Although single atom catalysts (SACs) have gained interest for the electrochemical reduction reactions of both carbon dioxide (CO2RR) and nitrate (NO3RR), the structure–activity relationship for Cu SAC coordination for these reactions remains unclear and should be explored such that a fundamental understanding is developed. To this end, the role of the Cu coordination structure is investigated in dictating the activity and selectivity for the CO2RR and NO3RR. In agreement with the density functional theory calculations, it is revealed that Cu‐N4 sites exhibit higher intrinsic activity toward the CO2RR, whilst both Cu‐N4 and Cu‐N4−x‐Cx sites are active toward the NO3RR. Leveraging these findings, CO2RR and NO3RR are coupled for the formation of urea on Cu SACs, revealing the importance of *COOH binding as a critical parameter determining the catalytic activity for urea production. To the best of the authors’ knowledge, this is the first report employing SACs for electrochemical urea synthesis from CO2RR and NO3RR, which achieves a Faradaic efficiency of 28% for urea production with a current density of −27 mA cm–2 at −0.9 V versus the reversible hydrogen electrode.

Modulating the electronic structure of atomically dispersed active sites is promising to boost catalytic activity but is challenging to achieve. Here we show a cooperative Ni single‐atom‐on‐nanoparticle catalyst (NiSA/NP) prepared via direct solid‐state pyrolysis, where Ni nanoparticles donate electrons to Ni(i)−N−C sites via a network of carbon nanotubes, achieving a high CO current density of 346 mA cm−2 at −0.5 V vs RHE in an alkaline flow cell. When coupled with a NiFe‐based anode in a zero‐gap membrane electrolyzer, the catalyst delivers an industrially relevant CO current density of 310 mA cm−2 at a low cell voltage of −2.3 V, corresponding to an overall energy efficiency of 57 %. The superior CO2 electroreduction performance is attributed to the enhanced adsorption of key intermediate COOH* on the electron‐rich Ni single atoms, as well as a high density of active sites.

In this study, we propose a top-down approach for the controlled preparation of undercoordinated Ni–N x (Ni-hG) and Fe–N x (Fe-hG) catalysts within a holey graphene framework, for the electrochemical CO2 reduction reaction (CO2RR) to synthesis gas (syngas). Through the heat treatment of commercial-grade nitrogen-doped graphene, we prepared a defective holey graphene, which was then used as a platform to incorporate undercoordinated single atoms via carbon defect restoration, confirmed by a range of characterization techniques. We reveal that these Ni-hG and Fe-hG catalysts can be combined in any proportion to produce a desired syngas ratio (1–10) across a wide potential range (−0.6 to −1.1 V vs RHE), required commercially for the Fischer–Tropsch (F–T) synthesis of liquid fuels and chemicals. These findings are in agreement with our density functional theory calculations, which reveal that CO selectivity increases with a reduction in N coordination with Ni, while unsaturated Fe–N x sites favor the hydrogen evolution reaction (HER). The potential of these catalysts for scale up is further demonstrated by the unchanged selectivity at elevated temperature and stability in a high-throughput gas diffusion electrolyzer, displaying a high-mass-normalized activity of 275 mA mg–1 at a cell voltage of 2.5 V. Our results provide valuable insights into the implementation of a simple top-down approach for fabricating active undercoordinated single atom catalysts for decarbonized syngas generation.