Artist:Linkin Park 
Song: The Catalyst 
Album: A Thousand Suns (2010)
Guitarist: Brad Delson
Standard Tuning

Guitar starts at 1:58
 
Riff 1

(1:58-2:10) 

e|----------------------------------------------|
B|----------------------------------------------|
G|----------------------------------------------|
D|-7-7-7-7/12-12-12-12\-10-10-10-10/12-12-12-12-| (2x)
A|-5-5-5-5/10-10-10-10\--8--8--8--8/10-10-10-10-|
E|----------------------------------------------|

Riff 2

(2:10-2:18)

e|------------------------------------|
B|------------------------------------|
G|-5-5-5-5/7-7-7-7/9-9-9-9/-10-10\9-9-|
D|-x-x-x-x/x-x-x-x/x-x-x-x/--x--x\x-x-|
A|-3-3-3-3/5-5-5-5/7-7-7-7/--8--8\7-7-|
E|------------------------------------|


From 2:18-2:26 play Riff 1 again (1x)


Riff 3

(2:26-2:36)

e|----------------------------------------------------|
B|----------------------------------------------------|
G|-5-5-5-5/7-7-7-7/9-9-9-9/-10-10/-12-12/-14-14-14-14-|
D|-x-x-x-x/x-x-x-x/x-x-x-x/--x--x/--x--x/--x--x--x--x-|
A|-3-3-3-3/5-5-5-5/7-7-7-7/--8--8/-10-10/-12-12-12-12-|
E|----------------------------------------------------|

Riff 4

  (2:40-2:48)   (2:48-2:56)   (2:56-3:02)   (3:02-3:10)

e|-------------|-------------|-------------|-------------|
B|-------------|-------------|-------------|-------------|
G|---7-7-7-7---|---5-5-5-5---|---3-3-3-3---|-----------3-|
D|---7-7-7-7---|---5-5-5-5---|---3-3-3-3---|---2-2-2-2-3-|
A|---5-5-5-5---|---3-3-3-3---|---1-1-1-1---|---0-0-0-0-1-|
E|-------------|-------------|-------------|-------------|


From 3:10-3:24 play Riff 3 again en let the last note ring


Now the "Lift me up, let me go" part starts (no guitar from 3:24-4:22)


From 4:22 till the end strum an A octave on the 12th fret, it looks like this:

e|--------|
B|--------|
G|---14---|
D|----x---|
A|---12---|
E|--------|

Thats it, hope you liked it and don't forget to rate ;)