Though imaging-guided multimodal therapy has been demonstrated as an effective strategy to improve cancer diagnosis and therapy, challenge remains as to simplify the sophisticated synthesis procedure for the corresponding nanoagents. Herein, an in-situ one-step reduction-encapsulated method has been reported, for the first time, to synthesize multicore-shell polydopamine-coated Ag nanoparticles (AgNPs@PDA) as a cancer theranostic agent, integrating amplified photoacoustic imaging, enhanced photothermal therapy, and photothermal promoted dual tumor microenvironment-coactivated chemodynamic therapy. The photoacoustic signal and the photothermal conversion efficiency of AgNPs@PDA nanosystem present a 6.6- and 4.2-fold enhancement compared to those of M-AgNPs-PDA (simply mixing PDA and AgNPs) derived from the increased interface heat transfer coefficient and the stronger near-infrared absorption. Importantly, AgNPs@PDA coactivated by dual tumor microenvironment (TME) enables controllable long-term release of hydroxyl radicals (·OH) and toxic Ag⁺, which can be further promoted by near-infrared light irradiation. Moreover, the high efficiency of AgNPs@PDA nanosystem with prominent photoacoustic imaging-guided synergistic photothermal-chemodynamic cancer treatment is also found in in vitro and in vivo studies. As a special mention, the formation mechanism of the one-step synthesized multicore-shell nanomaterials is systematically investigated. This work provides a much simplified one-step synthesis method for the construction of a versatile nanoplatform for cancer theranostics with high efficacy.

Modulating the local coordination structure of metal single-atom catalysts (SACs) is extensively employed to tune the catalytic activity, but rarely involved in regulating the reaction pathway which fundamentally determines the product selectivity. Herein, we report that the product selectivity of electrochemical CO₂ reduction (CO₂RR) on the single-atom indium-N_xC_4−x (1 ≤ x ≤ 4) catalysts could be tuned from formate to CO by varying the carbon and nitrogen occupations in the first coordination sphere. Surprisingly, the optimal In SAC showed great promise for CO production with the maximum Faradic efficiency of 97%, greatly different from the reported In-based catalysts where the formate is the dominant product. Combined experimental verifications and theoretical simulations reveal that the selectivity switch from formate to CO on In SACs originates from active sites shift from indium center to the indium-adjacent carbon atom, where the indium site favors formate formation and the indium-adjacent carbon site prefers the CO pathway. The present work suggests the active sites in metal SACs may shift from the widely accepted metal center to surrounding carbon atoms, thereby offering a new implication to revisit the active sites for metal SACs.

Rational design of catalytic sites to activate the inert N≡N bond is of paramount importance to advance N₂ electroreduction. Here, guided by the theoretical predictions, we construct a NiFe layered double hydroxide (NiFe-LDH) nanosheet catalyst with a high density of electron-deficient sites, which were achieved by introducing oxygen vacancies in NiFe-LDH. Density functional theory calculations indicate that the electron-deficient sites show a much lower energy barrier (0.76 eV) for the potential determining step compared with that of the pristine NiFe-LDH (2.02 eV). Benefiting from this, the NiFe-LDH with oxygen vacancies exhibits the greatly improved electrocatalytic activity, presenting a high NH₃ yield rate of 19.44 µg·h^-1·mg_cat^-1, Faradaic efficiency of 19.41% at -0.20 V vs. reversible hydrogen electrode (RHE) in 0.1 M KOH electrolyte, as well as the outstanding stability. The present work not only provides an active electrocatalyst toward N₂ reduction but also offers a facile strategy to boost the N₂ reduction.