Synthetic methods that allow for the controlled design of well-defined Pt nanoparticles are highly desirable for fundamental catalysis research. In this work, we propose a strategy that allows precise and independent control of the Pt particle size and coverage. Our approach exploits the versatility of the atomic layer deposition (ALD) technique by combining two ALD processes for Pt using different reactants. The particle areal density is controlled by tailoring the number of ALD cycles using trimethyl(methylcyclopentadienyl)platinum and oxygen, while subsequent growth using the same Pt precursor in combination with nitrogen plasma allows for tuning of the particle size at the atomic level. The excellent control over the particle morphology is clearly demonstrated by means of in situ and ex situ X-ray fluorescence and grazing incidence small angle X-ray scattering experiments, providing information about the Pt loading, average particle dimensions, and mean center-to-center particle distance.

Monolithic solar water splitting devices consist of photovoltaic materials integrated with electrocatalysts and produce solar hydrogen by water splitting upon solar illumination in one device. Upscaling of monolithic solar water splitting devices is obstructed by high ohmic losses in the electrolyte due to long ionic transport distances. A new design overcomes the problem by introducing micron sized pores in a silicon wafer substrate coated with electrocatalysts. A porous solar hydrogen device was simulated by applying a current corresponding to ca. 10% solar-to-hydrogen efficiency. Porous monoliths of 550 μm thickness with varying pore size and spacing were fabricated by laser ablation and electrochemically characterized. Ohmic losses well below 100 mV were reached at 14.4% porosity with 77 μm pores spaced 250 μm apart in 0.25 M KOH electrolyte. In 1 M KOH, 100 mV was reached at 6% porosity with 1 mm pore spacing. Our results suggest ohmic losses below 50 mV can be achieved when using 10 μm thick substrates at 0.2% porosity. These findings make it possible for monolithic solar water splitting devices to be scaled without loss of efficiency. ■ INTRODUCTIONHydrogen is one of the promising energy vectors that will likely be part of the future sustainable energy portfolio. 1 Using sunlight to split water into hydrogen and oxygen is a viable option for solar hydrogen production and several technologies exist that achieve water splitting at high efficiency. 2 A direct way to produce solar hydrogen is by using a solar water splitting device which combines light absorption, charge separation and electrochemical reactions in an integrated device. 3 High solarto-hydrogen (STH) efficiencies are reached using high-end photovoltaics (PV) coupled to electrocatalysts submerged in concentrated aqueous electrolyte. 4−7 The use of robust earthabundant catalysts and stable light absorbing materials with suitable band gaps has also been demonstrated. 8−11 These approaches show great promise at lab scale and development of practical systems is ongoing. 12−16 Beside the performance of catalysts and light absorbers, cell design is important and ohmic losses need to be minimized to maximize overall efficiency. 17,18 There are two common design types. 19,20 In the "wired" design ( Figure 1A) planar anode and cathode have opposed surfaces at close proximity such that the interelectrode distance to be covered by ions in the liquid electrolyte is minimized. 9−11 The "wireless" or "monolithic" layout ( Figure 1B) simplifies cell design by eliminating electrical contacts and wires through integration of all components in a monolithic flat assembly. 10

were determined by X-ray diffraction, high resolution electron microscopy, energy dispersive spectroscopy and nitrogen adsorption. The antimicrobial potential of ZnO@ZIF-8 for reduction of microorganisms often implicated with catheter-associated urinary tract infections (CAUTIs) was studied in detail using four target pathogens, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Staphylococcus aureus. The ability of the compound to kill all four microorganisms in suspension was established and a minimum bactericidal concentration of 0.25 mg mL -1 was determined for each microorganism. ZnO@ZIF-8 compound was found to be no more toxic to Galleria mellonella than distilled water, which was assessed by injection of Galleria with 10 µL of ZnO@ZIF-8 of concentrations of up to 2 mg mL -1 . ZnO@ZIF-8 suspensions (2 mg mL -1 concentration) were able to reduce well-established biofilms of all four oraganisms containing between 10 7 and 10 9 CFU mL -1 to below limit of detection (BLD) over a 24-h period. Silicone-embedded ZnO@ZIF-8 (2wt.% or 4 wt.% ZnO@ZIF-8 loading) also demonstrated antimicrobial properties with all four microorganisms being eliminated from the surface within 24 h. The ZnO@ZIF-8 high potency and rapid anti-biofilm activity against all four test organisms coupled with its non-toxicity offers a new avenue for control of microbial colonization of catheters, which would ultimately result in reduction of CAUTIs.

Active sites in bifunctional zeolite catalysts were engineered using atomic layer deposition (ALD). Gallium acid and platinum metal sites were introduced to zeolites via ALD and investigated for a hydroconversion reaction.

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