A multi-functional layered double hydroxide (LDH)-modified BiVO4 photoanode exhibits a tremendous cathodic shift of the onset potential and more than 2-fold enhancement in the oxidation efficiency and IPCE value.
The development of earth-abundant semiconductor photoelectrodes is of great importance to high-efficiency and sustainable photoelectrochemical water splitting. Herein, a one-dimensional TiO2 array photoanode was sheathed with an ultrathin overlayer of phosphated nickel-chromium double-metal hydroxide by a photoassisted modification and deposition strategy. The core/shell array photoanode resulted in a large cathodic shift of photocurrent onset potential (≈200 mV). Nearly 100 % oxidative efficiency for PEC water oxidation was achieved over a wide range of potential. Mechanism studies show that the modification of phosphate leads to significantly improved charge separation. The amorphous hydroxide sheath could efficiently inhibit oxygen reduction reactions. Therefore, this strategy enables the simultaneous suppression of surface carrier recombination and back reactions, which is promising to improve the water oxidation efficiency of currently prevailing photoanodes.
Hydrotalcite-supported platinum nanocrystals (Pt NCs) were synthesized by a facile solution chemistry method, and then applied as an efficient catalyst for the selective hydrogenation of cinnamaldehyde (CMA) in neat water. The reduction of metal precursor ions was achieved in an aqueous solution at a low temperature (323 K), simultaneously accompanied by the crystallization of the hydrotalcite support. The size of the Pt NCs can be delicately tuned by the relative ratio of surfactant to metal precursor ions, and characterized by HRTEM and CO-adsorption infrared spectroscopy. The Pt particle sizes are closely associated with the hydrogenation selectivity toward cinnamyl alcohol (CMO), with a higher selectivity up to 85% over the larger-sized Pt in an aqueous medium. The effects of alkali (NaOH) on the catalytic performance were explored. The findings indicated that the addition of alkali enhances the selectivity toward CMO (to 90%). The catalysts showed high stability with a marginal decrease in activity and selectivity after repeated use. The hydrogenation products could be easily separated from the solvent by simple extraction, which is a greener and more convenient process than those using organic solvents.
At the late 1940s, 17β-HSD1 was discovered as the first member of the 17β-HSD family with its gene cloned. The three-dimensional structure of human 17β-HSD1 is the first example of any human steroid converting enzyme. The human enzyme's structure and biological function have thus been studied extensively in the last two decades. In humans, the enzyme is expressed in placenta, ovary, endometrium and breast. The high activity of estrogen activation provides the basis of 17β-HSD1's implication in estrogen-dependent diseases, such as breast cancer, endometriosis and non-small cell lung carcinomas. Its dual function in estrogen activation and androgen inactivation has been revealed in molecular and breast cancer cell levels, significantly stimulating the proliferation of such cells. The enzyme's overexpression in breast cancer was demonstrated by clinical samples. Inhibition of human 17β-HSD1 led to xenograft tumor shrinkage. Unfortunately, through decades of studies, there is still no drug using the enzyme's inhibitors available. This is due to the difficulty to get rid of the estrogenic activity of its inhibitors, which are mostly estrogen analogues. New non-steroid inhibitors for the enzyme provide new hope for non-estrogenic inhibitors of the enzyme.
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