We report a rational design of CaHPO(4)-α-amylase hybrid nanobiocatalytic system based on allosteric effect and an explanation of the increase in catalytic activity when certain enzymes are immobilized in specific nanomaterials. Employing a calcification approach in aqueous solutions, we acquired such new nanobiocatalytic systems with three different morphologies, i.e., nanoflowers, nanoplates, and parallel hexahedrons. Through studying enzymatic performance of these systems and free α-amylase with/without Ca(2+), we demonstrated how two factors, allosteric regulation and morphology of the as-synthesized nanostructures, predominantly influence enzymatic activity. Benefiting from both the allosteric modulation and its hierarchical structure, CaHPO(4)-α-amylase hybrid nanoflowers exhibited dramatically enhanced enzymatic activity. As a bonus, the new system we devised was found to enjoy higher stability and durability than free α-amylase plus Ca(2+).

The combination of gold and copper is a good way to pull down the cost of gold and ameliorate the instability of copper. Through shape control, the synergy of these two metals can be better exploited. Here, we report an aqueous phase route to the synthesis of pentacle gold–copper alloy nanocrystals with fivefold twinning, the size of which can be tuned in the range from 45 to 200 nm. The growth is found to start from a decahedral core, followed by protrusion of branches along twinning planes. Pentacle products display strong localized surface plasmon resonance peaks in the near-infrared region. Under irradiation by an 808-nm laser, 70-nm pentacle nanocrystals exhibit a notable photothermal effect to kill 4T1 murine breast tumours established on BALB/c mice. In addition, 70-nm pentacle nanocrystals show better catalytic activity than conventional citrate-coated 5-nm Au nanoparticles towards the reduction of p-nitrophenol to p-aminophenol by sodium borohydride.

Engineering electronic properties is a promising way to design nonprecious-metal or earth-abundant catalysts toward hydrogen evolution reaction (HER). Herein, we deposited catalytically active MoS flakes onto black phosphorus (BP) nanosheets to construct the MoS-BP interfaces. In this case, electrons flew from BP to MoS in MoS-BP nanosheets because of the higher Fermi level of BP than that of MoS. MoS-BP nanosheets exhibited remarkable HER performance with an overpotential of 85 mV at 10 mA cm. Due to the electron donation from BP to MoS, the exchange current density of MoS-BP reached 0.66 mA cm, which was 22 times higher than that of MoS. In addition, both the consecutive cyclic voltammetry and potentiostatic tests revealed the outstanding electrocatalytic stability of MoS-BP nanosheets. Our finding not only provides a superior HER catalyst, but also presents a straightforward strategy to design hybrid electrocatalysts.

Engineering electronic properties by elemental doping is a direct strategy to design efficient catalysts towards CO electroreduction. Atomically thin SnS nanosheets were modified by Ni doping for efficient electroreduction of CO . The introduction of Ni into SnS nanosheets significantly enhanced the current density and Faradaic efficiency for carbonaceous product relative to pristine SnS nanosheets. When the Ni content was 5 atm %, the Ni-doped SnS nanosheets achieved a remarkable Faradaic efficiency of 93 % for carbonaceous product with a current density of 19.6 mA cm at -0.9 V vs. RHE. A mechanistic study revealed that the Ni doping gave rise to a defect level and lowered the work function of SnS nanosheets, resulting in the promoted CO activation and thus improved performance in CO electroreduction.