Heterovalent doping in colloidal semiconductor nanocrystals (CSNCs), with provisions of extra electrons (n-type doping) or extra holes (p-type doping), could enhance their performance of optical and electronical properties. In view of the challenges imposed by the intrinsic self-purification, self-quenching, and self-compensation effects of CSNCs, we outline the progress on heterovalent doping in CSNCs, with particular focus on the cation-exchange-enabled tuning of dopant luminescence and electronic impurities. Thus, the well-defined substitutional or interstitial heterovalent doping in a deep position of an isolated nanocrystal has been fulfilled. We also envision that new coordination ligand-initiated cation exchange would bring about more choices of heterovalent dopants. With the aid of high-resolution characterization methods, the accurate atom-specific dopant location and distribution could be confirmed clearly. Finally, new applications, some of the remaining unanswered questions, and future directions of this field are presented.

The development of rechargeable Na–S batteries is very promising, thanks to their considerably high energy density, abundance of elements, and low costs and yet faces the issues of sluggish redox kinetics of S species and the polysulfide shuttle effect as well as Na dendrite growth. Following the theory-guided prediction, the rare-earth metal yttrium (Y)–N4 unit has been screened as a favorable Janus site for the chemical affinity of polysulfides and their electrocatalytic conversion, as well as reversible uniform Na deposition. To this end, we adopt a metal–organic framework (MOF) to prepare a single-atom hybrid with Y single atoms being incorporated into the nitrogen-doped rhombododecahedron carbon host (Y SAs/NC), which features favorable Janus properties of sodiophilicity and sulfiphilicity and thus presents highly desired electrochemical performance when used as a host of the sodium anode and the sulfur cathode of a Na–S full cell. Impressively, the Na–S full cell is capable of delivering a high capacity of 822 mAh g–1 and shows superdurable cyclability (97.5% capacity retention over 1000 cycles at a high current density of 5 A g–1). The proof-of-concept three-dimensional (3D) printed batteries and the Na–S pouch cell validate the potential practical applications of such Na–S batteries, shedding light on the development of promising Na–S full cells for future application in energy storage or power batteries.

Yolk–shell hybrid nanoparticles with noble metal core and programmed semiconductor shell composition may exhibit synergistic effects and tunable catalytic properties. In this work, the hydrothermal cation exchange synthesis of Au@ZnS–AgAuS yolk–shell nanocrystals (Y–S NCs) with well‐fabricated void size, grain‐boundary‐architectured ZnS–AgAuS shell and in situ generated Au cocatalyst are demonstrated. Starting from the novel cavity‐free Au@AgAuS core‐shell NCs, via aqueous cation exchange reaction with Zn2+, the gradual evolution with produced Au@ZnS–AgAuS Y–S NCs can be achieved successfully. This unprecedented evolution can be reasonably explained by cation exchange initialized chemical etching of Au core, followed by the diffusion through the shell to be AgAuS and then ZnS. By hydrothermal treatment provided optimal redox environment, Au ions in shell were partially reduced to be Au NCs on the surface. The UV–vis absorption spectra evolution and visible light photocatalytic performances, including improved photodegradation behavior and photocatalytic hydrogen evolution activity, have demonstrated their potential applications. This new one‐pot way to get diverse heterointerfaces for better photoinduced electron/hole separation synergistically can be anticipated for more kinds of photocatalytic organic synthesis.

Cs 2 AgBiBr 6 -and Cs 3 Bi 2 Br 9 -alternatives) photocatalysts in the long-wavelength range of visible light (Figure 4d; Table S2, Supporting Information), [49][50][51][52][53][54][55][56][57][58][59][60][61][62][63] and is expected to be further improved by integrated with suitable surface active sites.

It is highly challenging to design low-cost, efficient electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, a hierarchical heterostructure was constructed on three-dimensional (3D) Ni foam, which contains Ni 3 S 2 nanorods decorated with both Co 9 S 8 and amorphous MoS x nanosheets and Ni 3 S 2 nanowires decorated with amorphous MoS x nanosheets, namely, MoS x @Co 9 S 8 @Ni 3 S 2 / NF. The synergistic effects from the strong interactions of the heterointerface and unique hierarchical heterostructure endow the MoS x @Co 9 S 8 @Ni 3 S 2 /NF with abundant active sites and effective mass and electron transport pathways, resulting in excellent activity toward both HER and OER in 1 M KOH. It only gives a low overpotential of 76.5 mV to achieve 10 mA cm −2 for HER and a low overpotential of 310 mV to achieve 100 mA cm −2 for OER. Based on the superior catalytic activity of MoS x @Co 9 S 8 @Ni 3 S 2 /NF for OER and HER, we demonstrated the activity of overall water splitting using MoS x @Co 9 S 8 @Ni 3 S 2 /NF as both the anode and cathode. It shows a higher catalytic activity for overall water splitting with a low cell voltage of 1.52 V at 10 mA cm −2 than commercial Pt/C/NF||IrO 2 /NF (1.61 V) and superior stability. This work provides a platform for the design and preparation of efficient electrocatalysts with various hierarchical heterostructures.