It is still a major challenge for preparing semiconductor nanocrysals with controllable size, shape, and doping. Especially, the size of nanoparticles under 10 nm still remains a big challenge. To date, there are very few researches of the synthesis of SnO 2 nanocrystals by using biomolecule-assisted hydrothermal approach. SnO 2 is an n-type semiconductor with the free exciton Bohr radius of 2.7 nm. The degradation of rhodamine B (RhB), an organic dye, in aqueous suspension is selected as a probe reaction to evaluate the catalytic activity of semiconductor photocatalytic performance. Herein, we report a biomolecule-assisted hydrothermal route for generating SnO 2 with diameters <10 nm, which presents excellent photocatalytic degradation of RhB. Under the basic condition, the degradation of RhB is close to 100% within 150 min. The high degradation rate of RhB on the as-synthesized SnO 2 nanocrystals can be attributed to the small size. The degradation mechanism is also discussed.

A facile, highly stereo- and regioselective hydrometalation of alkynes generating alkenylmetal complex is disclosed for the first time from a reaction of alkyne, carboxylic acid, and a zerovalent group 10 transition metal complex M(PEt(3))(4) (M = Ni, Pd, Pt). A mechanistic study showed that the hydrometalation does not proceed via the reaction of alkyne with a hydridometal generated by the protonation of a carboxylic acid with Pt(PEt(3))(4), but proceeds via a reaction of an alkyne coordinate metal complex with the acid. This finding clarifies the long proposed reaction mechanism that operates via the generation of an alkenylpalladium intermediate and subsequent transformation of this complex in a variety of reactions catalyzed by a combination of Brϕnsted acid and Pd(0) complex. This finding also leads to the disclosure of an unprecedented reduction of alkynes with formic acid that can selectively produce cis-, trans-alkenes and alkanes by slightly tuning the conditions.

The introduction of oxygen vacancies (Ov) has been regarded as an effective method to enhance the catalytic performance of photoanodes in oxygen evolution reaction (OER). However,t heir stability under highly oxidizing environment is questionable but was rarely studied. Herein, NiFe-metal-organic framework (NiFe-MOFs) was conformally coated on oxygen-vacancy-richB iVO 4 (Ov-BiVO 4 )a st he protective layer and cocatalyst, forming ac ore-shell structure with caffeic acid as bridging agent. The as-synthesized Ov-BiVO 4 @NiFe-MOFs exhibits enhanced stability and aremarkable photocurrent density of 5.3 AE 0.15 mA cm À2 at 1.23 V( vs. RHE). The reduced coordination number of Ni(Fe)-O and elevated valence state of Ni(Fe) in NiFe-MOFs layer greatly bolster OER, and the shifting of oxygen evolution sites from Ov-BiVO 4 to NiFe-MOFs promotes Ov stabilization. Ovs can be effectively preserved by the coating of at hin NiFe-MOFs layer,l eading to ap hotoanode of enhanced photocurrent and stability.

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