NOVELTY - Powder catalytic material comprising neodymium cobalt niobate Nd3-xCoxNbO7 (I) is new.    USE - The powder photocatalytic material (I) is useful as ultra-thin film photovoltaic material and in porous nanocomposite for decomposition of water into hydrogen and for catalytic degradation of pollutants in water, where the organic pollutants are microcystin, methylene blue and sulfamethoxazole (all claimed).    ADVANTAGE - The powder photocatalytic material (I) can be obtained with good reproducibility and consistency.    DETAILED DESCRIPTION - Powder catalytic material comprising neodymium cobalt niobate of formula (I) is new.    x=0.5-1.    INDEPENDENT CLAIMS are also included for:    (1) porous nanocomposite of (I)-silicon zinc zeolite;    (2) preparation of (I);    (3) preparation of porous nanocomposite of (I)-silicon zinc zeolite, comprising (1) preparing silicon zinc zeolite under alkaline conditions by with a molar ratio silicon dioxide/zinc oxide of 5/45 by adding zinc oxide to silicate solution, while adding citric acid complexing agent (for complexation of the zinc ions to maintain the colloidal stability of the zinc in the alkaline solution, for suppressing the generation of zinc oxide or hydroxide, and increasing the zinc content of the molecular sieve framework and zeolite crystallinity), then after hydrothermal reaction for 5 hours, filtering and drying, followed by crushing and sieving to obtain the desired silicon zinc zeolite, where the high crystallinity zeolite is confirmed by XRD and FTIR of zinc into the framework of the molecular sieve, (2) impregnating by c the (I)-silicon zinc zeolite composite in which certain amount of (I) is weighed and dissolved in water to give a turbid liquid, then adding certain amount of zeolite and impregnating with stirring for 2 hours to obtain a uniform slurry, placing the slurry in an oven and drying, then baking at 120 degrees C for 10 hours and cooling to room temperature;    (4) preparation of photoelectrode of (I) comprising cleaning fluorine-doped tin oxide (FTO) glass substrate by forming chunks of FTO glass size in required size with an glass cutter on non-conductive surface, scribing the glass to a desired size along the scribe line, sequentially in lye, ultrasonic cleaning with acid for 10-15 minutes, washing with deionized water, and storing deionized water for further use, and then uniformly mixing a certain percentage of powdered (I), ethylcellulose and ethanol, adjusting the pH value, sonicating for 2 hours in an autoclave, heat-treating for some time and evaporating in rotary evaporator to produce the colloid of desired viscosity, then with automatic film coater pressing to a desired thickness of the colloid by coating onto pretreated FTO glass, after 120 degrees C drying 1 hours, calcining at 450 degrees C for 20 minutes in air, and finally calcining at 500 degrees C for 15 minutes to remove the residual organic film, after cooling to 80 degrees C in dark, adding hot dye solution and soaking for certain time, then remove the excess dye by rinsing with ethanol to obtain the photovoltaic electrode material;    (5) application of (I) or photovoltaic electrode material or the porous nanocomposite for decomposition of water into hydrogen, by utilizing xenon lamp or a high pressure mercury lamp as the light source, in a closed valve controlled by many inner tube loop reactor; and    (6) application of (I), photovoltaic electrode material or the porous nanocomposite for catalytic degradation of organic pollutants in water, under visible light, or xenon lamp as a light source, where three kinds of biodegradable organic pollutants that are degradable in water are microcystin, methylene blue and sulfamethoxazole.