A process produces methyl methacrylate by direct oxidative esterification of methacrolein. Methyl methacrylate is used in large amounts for producing polymers and copolymers with other polymerizable compounds. An optimized workup of the reactor discharge from the oxidative esterification of methacrolein allows for co-discharged fine catalyst particles to be very efficiently separated and optionally removed or recycled. In addition, this process can reduce the formation of byproducts in extended continuous operation compared to known variant. A reactor system contains stirrer configurations which allow virtually abrasion-free operation and thus a catalyst on-stream time of several years.

The present disclosure provides for methods for designing and constructing metal/semiconductor heterostructures as catalysts for a wide range of applications such as oxygen activation. In a particular aspect, the present disclosure provides for the manipulation of atomic structures at MJ/TiO.sub.2 interface (e.g., Au/TiO.sub.2 interface) that significantly alters the interfacial electron distribution and prompts O.sub.2 activation. In an aspect, the present disclosure provides for a M/TiO.sub.2 composites (e.g., heterostructures) having a N defect-free M/TiO.sub.2 interface and method of making the M/TiO.sub.2 composites having a defect-free M/TiO.sub.2 interface. The M can be Au, Ag, Cu, Al, Pt, Ni, or Pd, for example.

The present disclosure provides for methods for designing and constructing metal/semiconductor heterostructures as catalysts for a wide range of applications such as oxygen activation. In a particular aspect, the present disclosure provides for the manipulation of atomic structures at MJ/TiO.sub.2 interface (e.g., Au/TiO.sub.2 interface) that significantly alters the interfacial electron distribution and prompts O.sub.2 activation. In an aspect, the present disclosure provides for a M/TiO.sub.2 composites (e.g., heterostructures) having a N defect-free M/TiO.sub.2 interface and method of making the M/TiO.sub.2 composites having a defect-free M/TiO.sub.2 interface. The M can be Au, Ag, Cu, Al, Pt, Ni, or Pd, for example.

The present disclosure provides a method for preparing a degradative sol, the method comprising providing an aqueous dispersion of titanium dioxide nanoparticles, providing gold and/or silver precursor compound(s) to the dispersion, illuminating the dispersion with ultraviolet light to photodeposit gold and/or silver nanoparticles onto the titanium dioxide nanoparticles to obtain photocatalytic plasmonic nanoparticles having a plasmonic resonance frequency in visible spectrum of electromagnetic radiation, and providing the photocatalytic plasmonic nanoparticles as a degradative sol. The present disclosure also provides a degradative sol, a degradative surface, a method for providing a degradative surface and a method for degrading organic substances.

The present disclosure provides a method for preparing a degradative sol, the method comprising providing an aqueous dispersion of titanium dioxide nanoparticles, providing gold and/or silver precursor compound(s) to the dispersion, illuminating the dispersion with ultraviolet light to photodeposit gold and/or silver nanoparticles onto the titanium dioxide nanoparticles to obtain photocatalytic plasmonic nanoparticles having a plasmonic resonance frequency in visible spectrum of electromagnetic radiation, and providing the photocatalytic plasmonic nanoparticles as a degradative sol. The present disclosure also provides a degradative sol, a degradative surface, a method for providing a degradative surface and a method for degrading organic substances.

A catalyst comprising noble metal particles and titanium-containing particles. The noble metal particles and titanium-containing particles are disposed on an outer surface of a support. At least 20% by weight of the total weight of noble metal particles are adjacent to at least one titanium-containing particle. The noble metal particles have an average diameter of less than 15 nm, and the catalyst has an average diameter of at least 200 microns. A method for preparing methyl methacrylate from methacrolein and methanol using the catalyst is also disclosed.

A catalyst comprising noble metal particles and titanium-containing particles. The noble metal particles and titanium-containing particles are disposed on an outer surface of a support. At least 20% by weight of the total weight of noble metal particles are adjacent to at least one titanium-containing particle. The noble metal particles have an average diameter of less than 15 nm, and the catalyst has an average diameter of at least 200 microns. A method for preparing methyl methacrylate from methacrolein and methanol using the catalyst is also disclosed.

Methods for making a multilevel core-shell structure having a core/graphene-based shell structure are described. A method for making a core/graphene-based shell structure can include obtaining a composition that includes core nano- or microstructures and graphene-based structures having at least a portion of a surface coated with a curable organic material, where the core nano- or microstructures and graphene-based structures are dispersed throughout the composition and subjecting the composition to conditions that cure the organic material and allow the graphene-based structures to self-assemble around the core nano- or microstructures to produce a core/graphene-based shell structure that has a graphene-based shell encompassing a core nano- or microstructure.

Methods for making a multilevel core-shell structure having a core/graphene-based shell structure are described. A method for making a core/graphene-based shell structure can include obtaining a composition that includes core nano- or microstructures and graphene-based structures having at least a portion of a surface coated with a curable organic material, where the core nano- or microstructures and graphene-based structures are dispersed throughout the composition and subjecting the composition to conditions that cure the organic material and allow the graphene-based structures to self-assemble around the core nano- or microstructures to produce a core/graphene-based shell structure that has a graphene-based shell encompassing a core nano- or microstructure.

Photoreduction of graphene oxide, by UV-generated ketyl radicals, to graphene. The photoreduction is versatile and can be carried out in solution, solid-state, and even in polymer composites. Reduction of graphene oxide can take place in various polymer matrixes. Methods for producing graphene-supported metal nanoparticles by photoreduction. Graphene oxide and a metal nanoparticle precursor are simultaneously reduced by the action of photogenerated ketyl radicals. Photoreduction is performed on polymer composite films in one embodiment.