Efficiency of layered photocatalysts such as graphitic carbon nitride (g-CN) is still too low due to the poor utilization of photoexcited-charge carriers. The major drawback is that the weak van der Waals force among g-CN layers is unfavorable for the charge transfer between the adjacent layers and the intrinsically π-conjugated planes with inefficient random in-plane charge migration. Herein, an atomically dispersed Pd layered photocatalyst with both bridged sites of adjacent layers and surface-sites of g-CN is demonstrated, providing directional charge-transfer channels and targeting active sites for photocatalytic water reduction. Both theoretical prediction and empirical characterizations are conducted to achieve the successful synthesis of single-atom engineered Pd/g-CN hybrid and the excellent separation of charge transfer as well as the efficient photocatalytic hydrogen evolution, much better than that of the optimized Pt/g-CN benchmark. The finding in this work provides a rational way for tailoring the performance and engineering of single-atomic noble metal.

In article number https://doi.org/10.1002/adfm.201802169, Jiaguo Yu, Hao Ming Chen, and co‐workers demonstrate the construction of a single‐atom engineered Pd/g‐CN hybrid with directional charge transfer channels and targeting active sites by interlayer intercalation and a surface anchor of Pd atoms. This unique material shows excellent charge transfer/separation and efficient photocatalytic hydrogen evolution.

Real bifunctional electrocatalysts for hydrogen evolution reaction and oxygen evolution reaction have to be the ones that exhibit a steady configuration during/after reaction without irreversible structural transformation or surface reconstruction. Otherwise, they can be termed as “precatalysts” rather than real catalysts. Herein, through a strongly atomic metal–support interaction, single-atom dispersed catalysts decorating atomically dispersed Ru onto a nickel–vanadium layered double hydroxide (LDH) scaffold can exhibit excellent HER and OER activities. Both in situ X-ray absorption spectroscopy and operando Raman spectroscopic investigation clarify that the presence of atomic Ru on the surface of nickel–vanadium LDH is playing an imperative role in stabilizing the dangling bond-rich surface and further leads to a reconstruction-free surface. Through strong metal–support interaction provided by nickel–vanadium LDH, the significant interplay can stabilize the reactive atomic Ru site to reach a small fluctuation in oxidation state toward cathodic HER without reconstruction, while the atomic Ru site can stabilize the Ni site to have a greater structural tolerance toward both the bond constriction and structural distortion caused by oxidizing the Ni site during anodic OER and boost the oxidation state increase in the Ni site that contributes to its superior OER performance. Unlike numerous bifunctional catalysts that have suffered from the structural reconstruction/transformation for adapting the HER/OER cycles, the proposed Ru/Ni3V-LDH is characteristic of steady dual reactive sites with the presence of a strong metal–support interaction (i.e., Ru and Ni sites) for individual catalysis in water splitting and is revealed to be termed as a real bifunctional electrocatalyst.

Phosphide-based electrocatalysts exhibit high activities in alkaline solution toward overall water electrolysis. However, their real phases during catalysis have not been comprehensively identified, leading to improper advancement in material recognition and theoretical simulation. In this work, in situ spatially coherent transmitted X-ray diffraction and X-ray absorption spectroscopy were developed to probe Fe-doped cobalt phosphides, presenting superior catalytic activity and reaction kinetics for overall water electrolysis compared to pristine cobalt phosphides. The results showed that Fe dopants latched the crystallographic sites and stabilized the phosphide phase, which are the active species for hydrogen evolution reaction, while pristine cobalt phosphide transformed into hydroxides that impede the formation of active substances. Besides, Fe-doped cobalt phosphides swiftly converted into active-site confined oxyhydroxide for oxygen evolution reaction, achieving superb overall catalytic performance. The genuine materials unveiled during the electrocatalysis suggest that the appropriate catalytic mechanism correlates with the phase transition and crystalline transformation rate.

Solar-driven photocatalytic reactions can mildly activate hydrocarbon C–H bonds to produce value-added chemicals. However, the inefficient utilization of photogenerated carriers hinders the application. Here, we report reversible photochromic BiOBr (denoted as p-BiOBr) nanosheets that were colored by trapping photogenerated holes upon visible light irradiation and bleached by water oxidation to generate hydroxyl radicals, demonstrating enhanced carrier separation and water oxidation. The photocatalytic coupling and oxidation reactions of ethylbenzene were efficiently realized by p-BiOBr in a water-based medium under ambient temperature and pressure (apparent quantum yield is 14 times that of pristine BiOBr). The p-BiOBr nanosheets feature lattice disordered defects on the surface, providing rich uncoordinated catalytic sites and inducing structural distortions and lattice strain, which further leads to an altered band structure and significantly enhanced photocatalytic performances. These hole-trapping materials open up the possibility of substantially elevating the utilization efficiency of photogenerated holes for high-efficiency photocatalytic activation of various saturated C–H bonds.

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Figure 2. Schematic illustration, morphology, and atomic structure characterizations. a) The synthesis processes of Fe SAs/NPCFs and Fe SAs-Fe 2 P NPs/NPCFs catalysts. b) AC-HAADF-STEM (inset shows the corresponding structure model) and c) HAADF-STEM-EDS mapping of the as-synthesized Fe SAs/NPCFs catalyst. d) AC-HAADF-STEM (inset shows the corresponding structure model) and e) HAADF-STEM-EDS mapping of the as-synthesized Fe SAs-Fe 2 P NPs/NPCFs-2.5 catalyst.

The discovery of different binding receptors to allow rapid and high-sensitivity detection via a noninvasive urine test has become the goal for urothelial carcinoma (UC) diagnosis and surveillance. In this study, we developed a new screening membrane receptor platform for bladder cancer cells by integrating surface-enhanced Raman spectroscopy (SERS) with 4-aminothiophenol (4-ATP)-modified AuAg nanohollows upon NIR laser excitation. AuAg nanohollows have an absorption band at ∼630 nm, and slightly off-resonance 785 nm laser excitation is used for minimal photothermal effect. Using the same carbodiimide cross-linker chemistry to conjugate anti-EGFR, transferrin (TF), 4-carboxyphenylboronic acid (CPBA), folic acid (FA), and hyaluronic acid (HA) molecules, by screening the 4-ATP SERS signals intensity, we demonstrated that the targeting efficiency with the cost-effective CPBA molecule is comparable with the conjugation of anti-EGFR antibody to aggressive T24 cancer cells (high-grade), while weak intensity 4-ATP SERS responses to targets were obtained by grade-I RT4 bladder cancer cells, NIH/3T3 fibroblast cells, and SV-HUC1 bladder normal cells. This SERS nanoprobe platform makes primary bladder carcinoma screening from in vitro to ex vivo more straightforward. Our demonstration offers exciting potential for SERS screening of specific receptors on cancer cells of different grades and facilitates new opportunities ranging from surface engineering of SERS material tags to SERS imaging-guided and targeted phototherapy of cancer cells by controlling the laser powers.