6020
The results indicate that 1 ) the U value can affect the calculated energetic result significantly , not only the absolute adsorption energy but also the trend in adsorption energy ; 2 ) CO can directly react with surface lattice oxygen atoms ( O ( 2f ) / O ( 3f ) ) to form CO ( 2 ) via the Mars - van Krevelen reaction mechanism on both ( 110 ) - B and ( 111 ) - B ; 3 ) pre - adsorbed molecular O ( 2 ) can enhance CO oxidation through the channel in which it directly reacts with molecular CO to form CO ( 2 ) [ O ( 2 ) ( a ) + CO ( g ) --> CO ( 2 ) ( g ) + O ( a ) ] on ( 110 ) - A / ( 111 ) - A ; 4 ) CO oxidation is a structure - sensitive reaction , and the activation energy of CO oxidation follows the order of Co ( 3 ) O ( 4 ) ( 111 ) - A ( 0 . 78 eV ) > Co ( 3 ) O ( 4 ) ( 111 ) - B ( 0 . 68 eV ) > Co ( 3 ) O ( 4 ) ( 110 ) - A ( 0 . 51 eV ) > Co ( 3 ) O ( 4 ) ( 110 ) - B ( 0 . 41 eV ) , that is , the ( 110 ) surface shows higher reactivity for CO oxidation than the ( 111 ) surface ; 5 ) in addition to the O ( 2f ) , it was also found that Co ( 3 + ) is more active than Co ( 2 + ) , so both O ( 2f ) and Co ( 3 + ) control the catalytic activity of CO oxidation on Co ( 3 ) O ( 4 ) , as opposed to a previous DFT study which concluded that either Co ( 3 + ) or O ( 2f ) is the active site .
 Chemical: CO; Chemical: oxygen; Chemical: O; Chemical: O; Chemical: CO ( 2 ); Chemical: O ( 2 ); Chemical: CO; Chemical: CO; Chemical: CO ( 2 ); Chemical: O ( 2 ); Chemical: CO; Chemical: CO ( 2 ); Chemical: O; Chemical: CO; Chemical: CO; Chemical: Co ( 3 ) O ( 4 ); Chemical: Co ( 3 ) O ( 4 ); Chemical: Co ( 3 ) O ( 4 ); Chemical: Co ( 3 ) O ( 4 ); Chemical: CO; Chemical: O; Chemical: Co ( 3 + ); Chemical: Co ( 2 + ); Chemical: O; Chemical: Co ( 3 + ); Chemical: CO; Chemical: Co ( 3 ) O ( 4 ); Chemical: Co ( 3 + ); Chemical: O
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: CO; Chemical: oxygen; Chemical: O; Chemical: O; Chemical: CO ( 2 ); Chemical: O ( 2 ); Chemical: CO; Chemical: CO; Chemical: CO ( 2 ); Chemical: O ( 2 ); Chemical: CO; Chemical: CO ( 2 ); Chemical: O; Chemical: CO; Chemical: CO; Chemical: Co ( 3 ) O ( 4 ); Chemical: Co ( 3 ) O ( 4 ); Chemical: Co ( 3 ) O ( 4 ); Chemical: Co ( 3 ) O ( 4 ); Chemical: CO; Chemical: O; Chemical: Co ( 3 + ); Chemical: Co ( 2 + ); Chemical: O; Chemical: Co ( 3 + ); Chemical: CO; Chemical: Co ( 3 ) O ( 4 ); Chemical: Co ( 3 + ); Chemical: O