TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: When the nano-objects have a metal chalcogenide composition selected from metal sulfide, metal selenide, metal telluride, and metal arsenide, and the electrically powered electrode is an electrically powered cathode, then the method involves contacting an aqueous solution comprised of a metal salt, reducible chalcogen-containing substance, and water with the electrically powered cathode to form the metal chalcogenide nano-objects, where the cathode is powered at sufficient negative voltage to reduce the reducible chalcogen-containing substance to a chalcogenide species that complexes with the metal of the metal salt to form the metal chalcogenide nano-objects, where the metal is selected from cationic forms of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, W, Pd, Pt, Au, Ag, Cd, Hg, Ga, In, Tl, Ge, Sn, Pb, Sb, and/or Bi. When the nano-objects have a metal oxide composition, and the electrically powered electrode is an electrically powered cathode, then the method involves contacting an aqueous solution comprising a reducible metal oxide or hydroxide compound and water with the electrically powered cathode to form the metal oxide nano-objects, where the metal oxide composition is selected from oxides of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Hf, Ta, Mo, W, Ag, Pd, Pt, Ga, In, Tl, Ge, Sn, Pb, Sb, and/or Bi. When the nano-objects have a metal oxide composition, and the electrically powered electrode is an electrically powered anode, then the method involves contacting an aqueous solution containing a metal salt and water with the electrically powered anode to form the metal oxide nano-objects, where the anode is powered at sufficient positive voltage to provide oxide species that complex with the metal of the metal salt to form the metal oxide nano-objects, where the metal is selected from cationic forms of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Hf, Ta, Mo, W, Ag, Pd, Pt, Ga, In, Tl, Ge, Sn, Pb, Sb, and/or Bi. When the nano-objects have an elemental metal composition, and the electrically powered electrode is an electrically powered cathode, then the method involves contacting an aqueous solution comprising a reducible metal salt and water with the electrically powered cathode to form the elemental metal nano-objects, where the cathode is powered at sufficient negative voltage to reduce the reducible metal salt at a negative voltage insufficient to produce hydrogen from water, to form the elemental metal nano-objects, where the metal is selected from Cu, Pd, Pt, Rh, Ir, Ag, or Au. The aqueous solution is adjusted in pH to modify the shape of the metal-containing nano-objects. The nano-objects are dislodged from the electrode. The electrically powered electrode is, or is attached to, an electrically conductive functional substrate on which the metal-containing nano-objects are formed and remain attached. Preferred Components: The electrode contains on its surface an array of conductive nanoscopic projections pointed outwardly from the surface. The conductive nanoscopic projections comprise flakes of graphene. The aqueous solution further comprises a surface-active agent that interacts by coordinate bonds to surfaces of the metal-containing nano-objects. The reducible chalcogen-containing substance is a reducible sulfur-containing substance selected from sulfate, sulfite, elemental sulfur, thiosulfate, sulfur-containing amino acids, and sulfur-containing nucleobases; a reducible selenium-containing substance selected from selenate, selenite, elemental selenium, selenosulfate, selenium-containing amino acids, and selenium-containing nucleobases; reducible tellurium-containing substance selected from tellurate, tellurite, elemental tellurium, tellurium-containing amino acids, and tellurium-containing nucleobases; or reducible arsenic-containing substance selected from arsenate and arsenate compounds. The reducible metal oxide or hydroxide compound is an oxide or hydroxide of a first row transition metal. The reducible metal component includes at least one Fe(III)-containing compounds or materials. The metal chalcogenide composition has a composition of formula ((M'xM'1w-v)(+r))s(X(-m))z (I); Cu(InxGa1-x')X'2 (II); or M3SnX'4 (IV). The metal oxide nano-objects possess a spinel-type composition of formula: M'x1(M'1)3-xO4 (II), or M'yFe3-yO4.M' and M'1=transition metal cation;X=S, Se, Te, N, P, As, Sb, or Bi;w, v, x, s, r, m, and z=integer or fractional numbers that together maintain charge balancing;x'=integral or non-integral numerical value of 0-1;X'=S, Se, or Te;M=chalcophile metal other than Sn, preferably Cu, Fe, Zn, or Cd;x1=0.01-1.5;y=0.01-2. EXAMPLE - Cadmium chloride and sodium thiosulfate was dissolved in an acetate buffer containing 8 mm cadmium chloride, 8 mm sodium thiosulfate, and 340 mm sodium acetate with pH adjusted to 7. The carbon electrode of 2 cm2 surface area was placed in the solution and run at -420 mV (standard hydrogen electrode potential) using platinum wire as a counter-electrode. A silver/silver chloride electrode was used as reference. The solution was sparged with nitrogen continuously and stirred, to obtain cadmium sulfide (CdS) nanoparticles of 15 nm in diameter.